I would definitely agree with Long John Silver and Nicky Holiday. They both seemed like a good fit for villians with the Muppets. They were dramatic, over-the-top, and funny as well as evil. Long John was a little violent that was totally part of the character and Tim Curry balanced that with the role in a muppet movie very well.
Doc Holiday was good, but the fact that he really wanted to kill kermit made him a little bit too harsh for me. A little too mean for a villian, lol
Was there really a villian in MTM? I don't think so, maybe that fraud guy but he was in the movie for like only 5 minutes.
Singer from MFS was a good Muppet Villian too, but a little creepy at times. He worked really well with the Muppets though
Ms. Bitterman was just a typical cranky corporate female villian to me, she didn't really stand out. Just a "big mean boss lady" as Pepe would put it.
Nathan Lane as the security guard in LTS was Priceless! He was great at it and would make for an excellent major muppet movie villian, maybe they should have cast him as the rich dude in this new movie.