Why the hell is Danny so nerfed? Yeah, there's the normal explanation (Without nerfing, Danny would be the most overpowered character in the game), and Calamitous did seal his ghost powers in Toybots, but he was just as weak in the previous games. And don't give me the "holding back" explanation. Danny may be dumb, but he's not Too Dumb to Live.
I'm just as disappointed as you, to tell the truth. I assume it had something to do with the creators wanting each character to have the same power level, just in different categories (ghosts, magic, science, and...sponginess, I suppose) At least he seems to be the leader of the team during Battle for Volcano Island while Jimmy isn't there in spite of SpongeBob's constant spotlight hogging.
Why do Zim and Dib act as if they know the other Nicktoons? Sure Zim has been featured in three previous games before Unite! but Unite! is basically a canon in itself. Neither were in the last three Unite! games (Excluding GIR in Toybots and Zim in the DS version, but GIR wasn't feature in cutscenes of any and Zim was only featured in the DS version). The only thing that would make since is all the console storylines in the same game (Example: Wii cutscenes and storyline in Toybots are alittle different from the DS version, same for other three). Could it be that DS version Adaptation Distillations, but are still aligned canonically with the console version? Who knows I'm rambling on now.