I like Pokemon Trainer.
Because it's the only instance in the entire series in which you are forced to use a special move with no input on the player's behalf. I used the Screw Attack analogy earlier to explain this.
It also forces you to turn a matchup against your favor.
No. And I never said it did.
It doesn't force you to do anything at all. You chose to use Pokemon trainer and when you chose him you knew he was going to switch anytime he got KOed. So you chose to do that when you picked trainer.
I don't get this "they're the only one who does it" argument. Just because you're the only one doesn't make it unfair. There are a lot of characters who have weird attributes. Two ice climbers, Olimar's reliance on Pikmin, Yoshi's shield, Jiggly's shieldbreak KO, Lucario's strength increase, ZSS' armor pieces, Ness/Lucas' grab release, Squirtle's shellfifting, ROB's footstool animation, Sonic's nonsweetspotting recovery that leaves a spring on the ground, Pit's gimpable recovery (only one whose Up B isn't restored when he's attacked), Samus' Zair (ok well three characters can do that one), ZSS' tether (only one that doesn't leave you in helpless) Gliding (again only 3), MKs UP B (only one that leads to a glide), Peaches floating, Peach's ability to pull out items (beam sword), Marth's tippered attacks, etc.
My point is alot of characters have unique things that only they do. Its only unfair if it presents an extreme burden that places your character at a significant disadvantage (Or I suppose if it gives such a large advantage that they're broken good) and I don't believe that this does.
Samus' screw attack is really too different to compare. The only special move you can really compare it to is Zelda's.
And the ability to switch may sometimes turns a matchup against you but the ability to switch also can turn a matchup in your favor.
Of course I wouldn't be opposed if it was decided to have Charizard, Squirtle, and Ivy as their own characters. It would be fun but I don't think its necessary or that the current system is unfair.