Actually, as far as I'm concerned, Next-Gen Sonic is the main game that suffered from rushed development. It was so rushed, that they didn't even have time to add in the "Super Gem", which allowed Sonic to transform into Super Sonic at any stage. It was supposed to've been unlocked after getting all S-Ranks, or whatever.
Anyway, about NiGHTS I think the game looks promising, after seeing the trailer. Since I actually have a Wii now, I might consider buying it.