So at six pages and counting, I've run out of space for all the ETAs on this thing. I'm also thinking this is gone from interest check to 'I think I'm actually developing this thing'. So, here's the current status:
It's going to be modern day or near future. Big metropolis in a fictional new offshoot off of the Washington state coast, a made up county that stretches out into the Pacific in a wing-shape. In it is the big city that is the main setting for the game. There's also going to be a new fictional mountain range and stuff because Pacific Northwest, but I'll figure out those details later.
The city will have neighborhoods, but not with any hard limit as to who can play what where - more simply realistic, like how any big city's downtown will have a different feel from the harbor area, etc. It will have a grid with rooms etc, though I haven't yet decided on the actual layout I want. I think that's still for later.
There's going to be a few permanent pocket dimensions as well, one of which goes into a noir-ish 1940s little alternative reality of the big city. The city (maybe the world? undecided) also has temporary pocket dimensions/gateways open up now and then, causing havoc and mayhem or miraculous goodness or just weirdness.
Outside of that small piece of the planet, Earth itself is the equivalent of Australia as far as other aliens are concerned. Massive cred to @Flitcraft for this idea. It's a place used as a dumping ground by various stellar polities. They drop criminals and wannabe Napoleons and various undesirables here, with the understanding that the few that aren't killed by the native species (i.e, humans) still won't be able to get off the backwater piece of rock. I am debating if there might or might not still be the equivalent of local 'space cops' touring the area on a regular basis to make sure there's no equivalent of life boats gunning for Saturn or such.
I am going to take the time today and tomorrow and really dig into ICONS. I'm currently looking between it ( this ICONS to be specific since there's multiples: https://greenroninstore.com/products/icons-superpowered-roleplaying-the-assembled-edition ) and good ol' M&M3E.
As far as character concepts go, power origins etc will be up to the players, but I will offer some pre-made options that should also help foster RP hooks. There's an evil corporation out there that likes to try and create mutants for them to control, super villains to like to create robots/summon elsedimensional or mystical beings etc, an unknown genetic strain that sometimes becomes dominant and changes the human into an Advanced Human, the destined wielder of the Force of Blah, etc, etc. Probably somewhere along the lines of five to seven or so more common sources.
Map: