This was something that disappointed me a little with the DS version, because you DO fight a final creature thing (the Mother Wisp or whatever) out in space as Super Sonic. If I remember right, the fight was embarrassingly easy, as well.
The Eggman boss in Colors DS was good, though, and the one in the Wii version was fantastic.
Yeah, I was floored at how well the Streetboarding in Rooftop Run mission worked. It was still a little janky in spots, but nowhere near what it could've been, and it was a lot of fun to take a very different approach to basically the same level.