I actually liked the trailer as well and am looking forward to seeing this. I am also keeping an open mind about Leto's Joker, he was depicted many different ways in the comics and films so I am open to a different interpretation.
That being said, I think they should have kept the mystery going a bit more and not showed as much of him as they did. While only maybe 10-15 seconds, we got to hear a kind of laugh, Hear him speak 2 sentences and see a close up of his face.
I think they could have had the laugh and the walk with his face obscured and leave out the talking. Either that or we can hear his dialogue but no picture of his face. To me seeing another Joker is the biggest draw to this movie for the casual fans (and people who watched previous Batman movies but not comic fans per-say), but with this trailer they kind of lay out too much.
