Greg Weisman was born to writer Emperor Palpatine. This is a perfect combination in my opinion.
I dunno... I'm not sure Palps is a subtle or intelligent enough character to be up to Weisman's standards of villain writing. Not every bad guy can be a Xanatos.
I know its been a while but...
I don't know Weisman's Doc Ock was a pretty cartoony super villain and he sure as hell didn't seem subtle.
But he wasn't the show's mastermind, just a subordinate. He'd compare to someone like Sevarius or Wolf. The masterminds in Spectacular Spider-Man were Osborn and Tombstone, though I believe it was Tombstone (who was reimagined as basically the show's surrogate Kingpin) who was the Xanatos-like schemer.