This is more of a response to Anno, but might as well. Creating your own villains is not a good measure of creativity. The MTV show also made up a majority of the villains, but all of them ended up being lame. Does that make it a more creative show than TSSM?
And really, aside from Harley and arguably Renee, did any of them ended up making ANY impact beyond the show? Were guys like Red Claw, the Sewer King, Roland Daggett, Boss Biggis, or Nostromos really that "interesting"? Even the better one-shots like Baby Doll and Calendar Girl were just that, one-shots.
It's not even a new thing for other media to be adapted to comics. Many elements that are well-known about Superman were not in the original comics (kryptonite, flight, etc.), but were first introduced by the old radio show. Firestar from Spider-Man and his Amazing Friends was introduced in the show in 1981, but was put into the main comics four years later.
The crew didn't want to create new characters in order to challenge themselves and use the Spider-Man universe to its fullest extents. Last time I check, challenging and pushing yourself to do your best is NOT a bad thing, and setting limits for yourself actually pushes creativity to it's highest.
And, once again, the whole "SSM hasn't influenced comics like B:TAS did" is stupid, since, once again, it took years for the latter to actually influence the comic world. Once more, let's wait and see a few years.