actually... crono was never a character considered for smash brothers brawl...
he was just one of the many (as said, with mega man, solid snake, etc.) POSSIBLE choices that non-nintendo companies could add. cloud strife and sephiroth were mentioned, too...
(please - no more sephiroth!)
and here's the thing. i think square enix KNOWS about us (the fan community) and our innate desire to see a third Chrono game. i think it comes down to logistics:
1.) to unite everyone involved to create Chrono 3
2.) to ensure their assets (we all know that in recent years square enix has not necessarily been what it once was)
i think the most logical point right now is a DS port of Chrono Trigger...
...and thats my two cents.
namaste.