To be honest, it doesn't look too bad. The City streets look just as the Thief City streets should look like - crooked, condensed, medieval, charming. The thief now has a number of abilities that a master thief logically should have - such as the ability to dart swiftly and quietly behind a target's back to avoid detection, which is a lot more sensible than "hiding" in a brightly-lit corridor in plain sight just because you know the AI isn't going to look back. If the original Thief games weren't constrained by the hardware/software limitations of their time, they would have had many of the same mechanics too.
Focus field seems like a fairly boring function, but you don't have to use it if you don't like it - just don't press the fucking button, or set the key to void in the options. Didn't hear any of the alleged "annoying whispers" in the video, btw. All the hand-holding can be turned off, and the change in light-gem gradation make sense - Thief always had three visibility states - total darkness, where you're completely invisible, partial shadow where guards begin to suspect something is wrong and start to walk in your direction, and bright light, where you can be seen by anyone who looks in your direction. Any gradations beyond this are extraneous - they add no relevant information.
And then there's the fact that new Thief threw out all the Hammers, Pagans, and Keeper stuff, and instead seems to go for a more "realistic" medieval/Victorian setting - well, in Thief, the story and setting always served the gameplay, and there doesn't seem to be anything terribly objectionable about the setting and story, aside from the fact that it's different from original Thief, so maybe give it a try?
I didn't get the lockpicking minigame, though - why do you sometimes see what's going on inside the lock mechanism and have to manually set the heights, and sometimes do it blindly? And I don't like that Garret's hands are now always visible when you walk, even if you're not holding a weapon or doing anything.
All in all, seems like a worthy remake of a classic stealth game series.
