Good news. They posted an update clarifying some of the things said in the vid.
"Hey guys, I think I might not have illustrated some of my points clearly on the video. It’s not correct to say that we’re trying to make Thief ‘mainstream’, or that we’re trying to make Garrett ‘less gothic’... This isn’t the case.
I was referring specifically to a previous Garrett design we tried out internally and not Garrett from the previous games. Our early design went a LOT more gothic – with black nails etc - but we thought that this wasn’t true to the legacy of Garrett so we pulled it back a bit. Returning to something more true to the original Garrett is what I meant when I said we made him more ‘mainstream’, this wasn’t a comment about the direction of the game.
I can assure you we’re huge fans of the original games and we’ve done our homework to create a game that maintains the essence of the original. I can’t wait to show you more of the game and Garrett soon!”