I'm more for replacing Pikachu than replacing Ash. Ash starts fresh in all regions, but what's the point of starting fresh if his starter is Level 100? At least he should be Level 100, yet he still lost to a Level 5 Snivy, which should have fainted just from a Tackle. Nerfing Pikachu is just wrong. It makes the whole previous seasons meaningless if he's still weak and only wins the most important battle (except League).
Seriously, can't Pikachu just tag along as a friend, and not "Pokemon"? What's the point of having a variety of new Pokemon, if Ash's gonna use Pikachu and win all important battles. I've watched the Elesa gym battle recently, and I was surprised when Ash decided not to use Pikachu, only to use him as his third Pokemon. Not cool man.