I have an RP idea but I need you to give feedback please so the story is (not as long as it will be) Mew had a protector who was it's friend swell but suddenly team rocket killed him to try and get mew. All the other teams in the other regions heard about this and also found out mew had escaped and ran off to a faraway region. The people of the region heard about this and had a massive breakdown on society trying to get mew and have it's powers for their own. A few people were summoned by mew to take out the Massive threats and try and stop all the civilians from trying to get mew. All champions that took down the teams of their home region died in a battle that went on for months many were killed. No one thought mew survived but it is in big danger being held hostage by Ghetsis with Mewtwo, Genesect and Kyurem. Professor Oak knew that and has now asked trainers from each region to help take down Team Plasma and save the world before it is destroyed.
What do you think?
Well, I have plenty of smaller questions...but there's one comment I have to make. It seems that you are trying to do everything to make something cool and appealing (such as bringing in all the teams, all the champions), but you have to focus this down. For instance, Plasma has no interest in destroying the world. Heck, none of the team leaders do, because it would mean certain death for them as well and none of them are suicidal.
Now, supposing that Mew does have this kind of incredible power, why doesn't it just take down Ghetsis? Sure, it's fun loving, but I can't see Mew as being the type to put itself, as well as the entire world, into grave danger for the sake of...nothing.
Plus, most of the other teams are dissolved. I'm not saying it's unreasonable that they would revive themselves if they had the motivation, but I think that the only one that would really go after Mew is Giovanni of Team Rocket, but his supposedly evil motivation is mostly brought on by his ambitions, so whether he'd actually do anything with Mew were he to obtain it...is pretty debatable, but you could certainly justify it in the RP. After all, Mew is still a mystery. Now, you do mention that they learn exactly what his power is, which could possibly catch the attention of Ghetsis as well, but not to the point where he would want to take over the world with it. Heck, if he had Mewtwo, Genesect, and Kyurem on his side, I think he'd be more than powerful enough to take over the world and destroy it.
As for the new region, why does it's society breakdown? I mean, I can understand that Mew is in the region and people want it, but there'd have to be some larger reason that this happens. What's more, why does everyone want it? I mean, sure, the Mew's powerful, but consider that quite a few incredibly strong legends have their locations known and they don't cause any sort of conflict (most of the time).
And how does Mew summon people? I'm not really sure how that works.