TL;DR: Not a successor to the Thief-Franchise but (except for the story) a damn good stealth-game on its own.


As you might imagine, I do not have much experience with the Thief franchise, due to me being of very young age. I wasn't even born when the first Thief was released. However, I do have experience with stealth-games in general, and I hope to bring you a detailed insight of Thief 2014 and answer your question if you should buy it or not.

STORY
The Story begins with Garrett robbing a Safe for an expensive necklace. After he escapes the attic he found the safe in, he meets his friend Erin, who leads Garrett through a kind-of-tutorial-area. At the end of the mission, the two observe a group of people who look like priests or monks performing a ritual in front of something called the 'Primal Stone'. The Building Collapses, Erin falls down and dies, Garrett falls down, survives, but falls unconscious.
A Year later, Garrett wakes up while two beggars try to smuggle his body into his hideout in the clocktower in the center of the city. The smuggling attempt fails, one beggar is killed, the other runs away and Garrett is on his own, with the claw he "inherited" from Erin. He later learns that the main antagonist is still alive, and that a plague-like disease, the "Gloom" is running about in the city.
Garrett now works for several sides, his fence Basso, Orion, the leader of the resistance, and as a freelance to discover the secret behind his hallucinations of Erin in some kind of otherworld.

HUBWORLD / THIEVERY
In the Hubworld you can take side-missions or go and heist houses at your own leisure. There's loot everywhere and some guards even carry little valuables on their belt, which you can either take by taking up their body after you killed / knocked them unconscious, or you can pickpocket the loot from them. There are also merchants who sell you various types of arrows, and quest-givers, who... well... give quests.

MOVEMENT
Garrett moves at a medium pace, and you can hold CTRL to walk over glass shards or through water quietly, or you can sprint by holding shift.
While you cannot jump in place anymore, Spacebar has turned into one button for a little dash which you can use as a crouched sprint, and you can sprint with shift and hold spacebar to turn it into an automatic climbing button.

COMBAT: Blackjack
Garrett carries a bow and a blackjack, but not a sword anymore.
Also, you can't equip the blackjack anymore, but swing it directly. Further, there's a dodge-button which helps you in combat. 3 Hits with the Blackjack while evading enemy hits will usually trigger an optional button to instantly knock out the guard. Without the Bow, you can NOT kill or civilians anymore.

THE BOW
The Bow is your all-purpose-weapon. You can shoot regular arrows to snipe enemies, water arrows to extinguish light sources, gas arrows to knock out birds, dogs and other potential troublemakers, and blunt-headed arrows which you can carry in great amounts to trigger buttons from afar.
One VERY big flaw for me is that you can shoot rope arrows only at pre-determined locations now, instead of wood in general. This eliminates the whole purpose of using a rope to climb unclimbable terrain. Now it's REQUIRED to reach certain locations, and the feeling of "being smarter than the game" which you had in the old Thief games is now gone.

MISSION DESIGN
The side jobs are manifestations of the thief formula: go to x, steal y and, sometimes, bring it to z. For every side mission you receive a small amount of gold, sometimes a few hundred, sometimes the reward is a piece of loot that's worth 50 gold.
One problem is the amount of side missions there are in the game. If you do them all, you will never face financial problems and be able to buy everything, at least below master difficulty. In the Master difficulty grade, arrows and gadgets are considerably harder to come by, and at some point you will have to decide what type of arrows you want.

The Story Missions are horribly designed. Sometimes the game crosses Horror territory,
WALKING THROUGH AN ASYLUM WITH NO ENEMIES AROUND AND PICKING RANDOM LOCKS TO TRIGGER STORY PROGRESS DOES NOT BELONG IN A STEALTH-GAME.
Sometimes it throws you into a room with 4 or more enemies, aware of your presence, and with the objective set near an un-extinguishable lightsource, forcing you to kill or knock out everyone around.

GRAPHICS, PERFORMANCE
The game runs buttery smooth on my Phenom II X4 965 BE and Radeon HD 7850, without AA and V-Sync. Shadows look great even on medium settings and the textures reach from okay to sexual intercourse for the eye.

PERFORMANCE OPTIONS
The list is too extensive to describe in in detail here, but I will give you an example:
Imagine the settings "Graphic quality: Low/Medium/High"
Thief's graphic settings are the opposite of that.
Also: FOV goes up to 110°.

GAMEPLAY SETTINGS / DIFFICULTY SETTINGS
You can create a custom game-mode with special limitations. There are many options, from "you can't use broadhead and sawtooth arrows" to "if you die your savegame is deleted". All of these options increase the score you get in the game, which is shared on a global leaderboard, if you choose so.


Overall, Thief is a nice game. The thievery and movement feels right, and aside from some really ♥♥♥♥♥♥ up main missions, it's a blast to play. I bought it in a bundle for 9€ and ♥♥♥♥♥♥♥♥♥, this game for 9€? Worth every penny.
Thief 2014, Thief 4, Thief Reboot, Thief Remastered, Thief whatever the ♥♥♥♥ you'd like to call it, is dragged down by comparisons to the older Thief titles, which were better than this game. This does not mean that this game is bad, though.

TL;DR: Not a successor to the Thief-Franchise but (except for the story) a damn good stealth-game on its own. As you might imagine, I do not have much experience with the Thief franchise, due to me being of very young age. I wasn't even born when the first Thief was released. However, I do have experience with stealth-games in general, and I hope to bring you a detailed insight of Thief 2014 and answer your question if you should buy it or not. STORY The Story begins with Garrett robbing a Safe for an expensive necklace. After he escapes the attic he found the safe in, he meets his friend Erin, who leads Garrett through a kind-of-tutorial-area. At the end of the mission, the two observe a group of people who look like priests or monks performing a ritual in front of something called the 'Primal Stone'. The Building Collapses, Erin falls down and dies, Garrett falls down, survives, but falls unconscious. A Year later, Garrett wakes up while two beggars try to smuggle his body into his hideout in the clocktower in the center of the city. The smuggling attempt fails, one beggar is killed, the other runs away and Garrett is on his own, with the claw he "inherited" from Erin. He later learns that the main antagonist is still alive, and that a plague-like disease, the "Gloom" is running about in the city. Garrett now works for several sides, his fence Basso, Orion, the leader of the resistance, and as a freelance to discover the secret behind his hallucinations of Erin in some kind of otherworld. HUBWORLD / THIEVERY In the Hubworld you can take side-missions or go and heist houses at your own leisure. There's loot everywhere and some guards even carry little valuables on their belt, which you can either take by taking up their body after you killed / knocked them unconscious, or you can pickpocket the loot from them. There are also merchants who sell you various types of arrows, and quest-givers, who... well... give quests. MOVEMENT Garrett moves at a medium pace, and you can hold CTRL to walk over glass shards or through water quietly, or you can sprint by holding shift. While you cannot jump in place anymore, Spacebar has turned into one button for a little dash which you can use as a crouched sprint, and you can sprint with shift and hold spacebar to turn it into an automatic climbing button. COMBAT: Blackjack Garrett carries a bow and a blackjack, but not a sword anymore. Also, you can't equip the blackjack anymore, but swing it directly. Further, there's a dodge-button which helps you in combat. 3 Hits with the Blackjack while evading enemy hits will usually trigger an optional button to instantly knock out the guard. Without the Bow, you can NOT kill or civilians anymore. THE BOW The Bow is your all-purpose-weapon. You can shoot regular arrows to snipe enemies, water arrows to extinguish light sources, gas arrows to knock out birds, dogs and other potential troublemakers, and blunt-headed arrows which you can carry in great amounts to trigger buttons from afar. One VERY big flaw for me is that you can shoot rope arrows only at pre-determined locations now, instead of wood in general. This eliminates the whole purpose of using a rope to climb unclimbable terrain. Now it's REQUIRED to reach certain locations, and the feeling of "being smarter than the game" which you had in the old Thief games is now gone. MISSION DESIGN The side jobs are manifestations of the thief formula: go to x, steal y and, sometimes, bring it to z. For every side mission you receive a small amount of gold, sometimes a few hundred, sometimes the reward is a piece of loot that's worth 50 gold. One problem is the amount of side missions there are in the game. If you do them all, you will never face financial problems and be able to buy everything, at least below master difficulty. In the Master difficulty grade, arrows and gadgets are considerably harder to come by, and at some point you will have to decide what type of arrows you want. The Story Missions are horribly designed. Sometimes the game crosses Horror territory, WALKING THROUGH AN ASYLUM WITH NO ENEMIES AROUND AND PICKING RANDOM LOCKS TO TRIGGER STORY PROGRESS DOES NOT BELONG IN A STEALTH-GAME. Sometimes it throws you into a room with 4 or more enemies, aware of your presence, and with the objective set near an un-extinguishable lightsource, forcing you to kill or knock out everyone around. GRAPHICS, PERFORMANCE The game runs buttery smooth on my Phenom II X4 965 BE and Radeon HD 7850, without AA and V-Sync. Shadows look great even on medium settings and the textures reach from okay to sexual intercourse for the eye. PERFORMANCE OPTIONS The list is too extensive to describe in in detail here, but I will give you an example: Imagine the settings "Graphic quality: Low/Medium/High" Thief's graphic settings are the opposite of that. Also: FOV goes up to 110°. GAMEPLAY SETTINGS / DIFFICULTY SETTINGS You can create a custom game-mode with special limitations. There are many options, from "you can't use broadhead and sawtooth arrows" to "if you die your savegame is deleted". All of these options increase the score you get in the game, which is shared on a global leaderboard, if you choose so. Overall, Thief is a nice game. The thievery and movement feels right, and aside from some really fucked up main missions, it's a blast to play. I bought it in a bundle for 9€ and holy shit, this game for 9€? Worth every penny. Thief 2014, Thief 4, Thief Reboot, Thief Remastered, Thief whatever the fuck you'd like to call it, is dragged down by comparisons to the older Thief titles, which were better than this game. This does not mean that this game is bad, though.