Blaziken would make a decent Captain falcon clone funny enough. I believe after the big five, Blaziken would be next, however I just don't see any of the five getting kicked for the bird. With Mario having five hard reps now (and three soft reps) I don't see the problem with pokemon having 5 reps (with the extra +2 poke trainer brings).
As far as the talk about 1st gen representation goes, I don't get this argument at all. I mean it's basically the recency argument or the new vs old argument, which has been proven time again is bogus. Generation 1 love it or hate it, has had more time to develop it's characters and thus has more support generally. Granted, it would be nice to have newer representation such as say Blaziken or Zoroark, but can anyone truly argue that any of the current reps are less important than they were in previous incarnations. Saying we should replace Jiggles or PT with say Zoroark or Blaziken is like saying we should replace Luigi with Bowser Jr.
I mean if you think about it most Hard mario reps are from the old school NES games (excluding Rosalina who could mirror Lucario). However no ever feels that the newer characters (Waluigi, Bowser jr, or Nabbit) should outright replace any of the established characters. Granted comparing Mario and Pokemon isn't the most solid of comparison due to the marketing and build of these games, but there is still truth in the matter.
Oh and Ivysaur is baller, don't let anyone tell you differently.