I strongly disagree with this. If anything, newer characters should be excluded for a year or so to see if they're still memorable enough after a year to be "the most popular character of the entire One Piece universe" (that's what this is about, after all). A tournament without, for example, Don Krieg or Bellemere or Zeff or Dalton or characters from Alabasta or Skypiea wouldn't be a proper tournament to me. Would you want to exclude Luffy? He is the oldest character (after Coby or Alvida I think) in the entire series.
That's just my opinion though. I think the sheer multitude of characters is one of the things that makes One Piece so awesome and I love remembering the older characters.
I also disagree with this. In my opinion, groups of characters (SH Grand Fleet) and jokes that are not really characters (Ryuunosuke, Fred) should be the ones excluded.
I'd be all for that tbh, but many people would probably think it'd get boring to have the same characters all over again (while you wait for another 2 years to allow the new ones). But ah well, it's not like it's the Olympic or anything. Just annoying when I see something like Ryuunosuke win against Zoro. Or Carrot against Garp.