You can't make any judgment on a trailer! There are a lot of games whose trailers looks great but the gameplay sucks! What's the use having features but the gameplay is not nice!
And i'm not saying it won't be nice you just can't make any judgment on a trailer!
I disagree. While a trailer won't decide whether I will buy a game or not, you can definitely make some kind of judgement on how the game looks. For example, the tackle animations shown in the trailer look smooth and realistic and having seen Rugby Challenge in action is backed up in game. Could you please tell me some games that have good trailers, but game play is bad?