While a healthy dose of competition is certainly good, I err on the side of socializing and fun in the local setting. Extraordinary players arise regardless of geography, and playing online facilitates this. It's cheaper to run tournaments in this way, and while at very high levels of play, we might all congregate in a location to see the finals or something live, it's less important, especially since access and streaming are possible now. So in this sense, I don't think competitive versus casual players is as much of an issue as say GCN Smash. SoulGuitarist also makes a good point about SSB versus Splatoon in terms of sameness. It is less like Mario games where there's more elements of randomness. Despite that, it's still fairly accessible to newcomers because there's also inking to be done, on top of shooting other players.
I think the main focus should be bringing everyone up to the same level and playing for fun. It feels really good to have someone you look up to teach you a cool skill; conversely, it's really rewarding to see newcomers finally getting the game. When I played Pokémon, veteran players would explain rules over and over again for the new players, and even offer to comment on decks, or outright give you some cards. When you lost, it was always shake hands, good game, and then discuss what just happened or watch the other games. Any question was a good question and would get answered without condescension or ridicule. Age wasn't a factor and it was so neat to see parents playing with, or little kids show older but newer players how things went. By no means was it perfect, but to just to say it, I only left because of geography and workload reasons, not because of drama or stuff like that. /coughmagicthegatheringcough/
It's neat that there's an assumption about having teams attend. I was thinking it was more of a pick-up type situation like Ishmael and Ansible were touching on. With regards to the number of people, I think we all agree that 4v4 is more fun than anything less, but there's also the new Salmon Run mode. So the minimum number of people that need to show up would be two, if we include Salmon Run as a mode of play. Teams would be really cool for tournaments and such, but my vision of local play was more of a casual, social thing. Maybe have a more spectator-y competitive tournament once in a while to make things interesting. Maybe having a local Splatfest where you can only use pre-specified loadout amiibo configs (in lieu of the shirt) and the winning side gets a small token to wear in commemoration or their names on a list like in an arcade.
For timelines, I thought it'd be a weekly or fortnightly, with these Splatfests running for two or three sessions each, and any sort of tournament on a seasonal or yearly basis.
But yeah. That venue problem.