What Marvel characters have the potential to substitute for others?

[Spider-Kurt!]

What I mean is due to legal issues the Kingpin isn't going to appear in a Spider-Man film or animated series. Several people here have mentioned how The Spectacular Spider-Man has done a great job of putting Tombstone in the Kingpin's role.

Also in Planet Hulk

Spoiler

Beta Ray Bill replaces the Silver Surfer from the original story.

What other Marvel characters do you feel could be suitable replacements?

 

[Spider-Kurt!]

I think a good example would be the Lizard replacing Vermin in an adaptation of Kraven's Last Hunt. It's been a very popular choice over on the Spider-Man movie boards for quite a while now.