Super Dante is not legal, because if it is, Dante can freeze everything indefinately, then Charged Nightmare Beta, kthxbye.

And I am aware that Dante can't legally use Sparda in Devil Mode. Again, if he can use that like he has in the legendary battle, he simply cannot be defeated.

What he has in DMC2 is, he has a different selection of swords, with 3, 4, 5, 6 hits combo, and each will do different things in Devil Mode. Also, he will go into Desperate (Ultimate) Devil Mode when his life turns red. He's look like a demon, just like in the Legnedary Battle in DMC1. His speed, attack, defense will further increase. (He won't last too long in the form though, because his life can still recover.)