K0rkki
Trainer
This kind of reminds me of the fisrt gen anime story... Go go prankster Jigglypuff. Anyways, if released pokemons were to follow you for revenge or sth. that should really be just an added chance to encounter whenever walking at tall grass etc. The chance of reappearing should be static and the attacking pokemon should be dunno, like randomed out of the tailing pokemons. That would prevent ppl from trying to release many pokemons and try to level up others by fighting those reappearing (with higher level). It would be also stupid if they came back too soon after the release. Would also be cool if they had only a chance of leaving you alone after defeat so you wouldn't ever know if someone is still tailing you. Oh, how about making them try to flee and reappear later if it gets too rough? xD The AI could even be made to focus on status effect (poison, paralyze, sleep...) dealing attacks following with fleeing on next turn. Throw in pumped defence, special defence and speed aswell. Naturally it should be made impossible to recapture those released ones if their stats and levels are altered. Man, all this would sum up to "annoying as hell"... As for dual battles, maybe released pokemons could bring a local pokemon from the area you are currently at and that one could also have higher level and maybe even evolved versions of the locals (a lvl 15 caterpie would be just silly...)