Do we really need trailers for trailers..? Marketing goes a bit a overboard these days. No wonder the big publishers are all suffering. When they spend $20-40 million on development and three times as much on marketing, it's going to be tough to make a profit.
Anyway, I haven't seen enough to make any judgment on the new Thief. The art style and premise are a bit too similar to Dishonored for my taste but if they deliver the strong stealth gameplay the series is known for, I'm okay with it. I'm hoping the trailer is actually a gameplay walkthrough.