The only thing I want to see is real gameplay. Trailers require a lot of work and money for some eye candy but without actually showing anything new. I think they shouldn't go down the Ubisoft route with multiple fancy trailers in only a few months. They should concentrate on the game itselft instead.
Show us what we really want to see and know. Show us PC gameplay, PS4 gameplay, mouse/keyboard gameplay (with UI), Geralt in a different set of armor, combat with real difficulty and so on.
You know, the REAL stuff not some fancy premade trailer. Quality and information over AAA hype, please. That's what I expect from CDPR in the next months and at Gamescom/PAX/IgroMir.