Well, having a pokemon world obviously has some big implications... About guns: since pokemon only obey under certain conditions, it would be easier to control than guns, which can technically be used by everyone that can pull a trigger. Why use a 'weapon' that, if taken over, could be used against you instead of one that only obeys you? (~Judge Dredd?) Much safer in that aspect. Also, there are so many pokemon, you can just get them out of the wild and start training. No factories required. (even though food could make it a bit expensive in some cases). And have you seen what some of them can do? As such, licenses would definitely be mandatory, unless (implicit) societal rules would already take care of the problems that regulations would do, or use of a gradation system (tied with the gym badges, kinda like Reborn) to restrict novices from having destructive and demanding pokemon. Legendaries shouldn't be captureable, or at least only with heavy-duty tools, yet illegal. Breeding should be regulated indeed, just as it actually should be in the real world. Ever been to an animal shelter? You know most of them are eventually killed (lethal injection) there, because they can't find anyone to take them? Yet people can't stop breeding more and more...it's kinda depressing. Economically, I really don't know how that would be regulated. How do you insert it onto people that, after they lost a battle, they have to gife half their money to the victor? Impossible? No. Difficult? Dark Souls-level. The main problems are fairy/psychic/ghost-types, survivability and energy, imo. About survivability: it is entirely possible that a pokemon that seems very fragile can survive in a certain niche. Think about Spoink as Dodo's. Those birds couldn't fly, yet they could survive (until exotic predators were introduced) because of the circumstances. Likewise, there's probably an environment in which Spoink could survive. Since you find them at Jagged Pass, their tail could actually be the key to their survival, since that would make them able to escape predators in their habitat. (by jumping over those damn ledges) So that's off the chart.
About energy: there are a lot of ways to store energy. Who knows what the hell those things get fed, or how frequent their 'power plays' are in nature. If they're so powerful they could destroy everything, maybe the fact that the world still exists could point to there not being enough energy in nature to provide endless rampaging. In the first season, prof. Oak introduced food that, with just a few blocks, could feed a snorlax. I guess that would be enough to provide a lot of energy to a pokemon to do some pretty powerful stuff. Check. Then there are Fairies, psychics and ghosts. I can't make a plea about how those could be possible. For example: at this moment, we only are able to control objects if you and the object are equipped with technology, but psychic-types would be able to do so without any of those. I don't know how this is possible without elecromagnetism, which wouldn't make it a psychic anymore. I guess the universe would need certain properties that would make it possible for those three types to exist. Something ours isn't capable of (in my current knowledge). Potato.
