Until visiting Japan I thought Pokken Tournament was unsucessful at all, in my country it's very rare to find "Tekken players which also like Pokemon" so it was a strange niche. Even national Facebook groups were desert here, so I had no hope this game would have a sequel.
After visiting Japan my impressions changed, almost every Pokecenter I did visit was full of kids playing together and enjoying at fullest (even some grow ups having fun too). Since Japan cares a lot about their own market, I have my fingers crossed on a sequel of this great game. I've bought both Wii U and Switch versions and all DLCs, even the controller (which's great to play retro fighting games too), so my part's done!
For the story, maybe some "evil organization" would do a nice new story mode with many battles and cool characters. Something like the previous one, "cursed powerful one", but in the hands of really bad guys.