It isn't too early... but it does feel early (to me at least). It's probably because we've started to associate a new game with a new system. But when you think about it Gold and Silver were branded as GameBoy titles not GBC, it was only Crystal that was branded a GBC title.
I'm still looking forward to the game but being on DS kind of reduces the anticipation. I was very curious to see the first Diamond/Pearl images just because of the technological leap - this time that is removed. It just feels a bit odd having five 4th generation titles and then two 5th generation. In the GB era we only had three 1st gen (exluding Green) and then three 2nd gen. But saying that Nintendo are eluding to some major changes so it could end up being one of the most interesting titles in a while.
In the end it doesn't matter much, as a fan I'd be happy with a new Pokemon game, but for now I'm just excited at the possibility of re-exploring Johto.