Looking at all of the Pokemon, I don't see them adding anymore, but is this about right?:
1. Lucario - Replaced Mewtwo - The most likely to be replaced. This slot is held for a significant movie Pokemon
2. Pokemon Trainer - 2nd most likely to be replaced / altered. For the 151 fags.
3. Jigglypuff - Veteran Smash Pokemon. Was significant back in the day. 3rd most likely.
4. Pikachu - The face of Pokemon. If replaced, would cause mass hysteria.
Although Jiggly won't be taken out, I think it and Lucario should be replaced with up to date Pokemon.
And I like Lucario.