well you said something about possibly adding ideas as maps and I've come with a literal list.

-skyscraper: a multi-level building where you have to move vertically up and down with two stair cases on different sides of the map. i'd guess sneaking on this map would be close to impossible with how tight it would be horizontally, but would really play into the idea of storming a building. it could also be filled with office desks and cubicles for blocking and possibly have an outside walkway/ramp.

-kingdom: a giant castle/mansion that's been left in disarray. i doubt the inside is all that crazy, maybe just 2 or 3 levels with a bunch of empty rooms, but it has a large outside surrounding it with a garden with those hedge walls and stuff.

-transit: a mix of the subway levels and the up high train tracks; this map is built around a stairwell (a pretty wide one) from a city block towards an underground train station. it could have multiple large openings, making it a perfect place to hold positions or to escape from.

-island: a small island with a massive building in the center, it's a small map with limited space to play with and even fewer things to hide behind, making battles difficult. i can only imagine this as plastic beach.

-Colosseum: the roman Colosseum as a map. i have no idea how to implement this, but thought it should be brought up.

-stone hedge: we need the big alien destination represented in this game, add stone hedge

-pyramids: along with alien destinations, why not the inside of an Egyptian tomb, no idea why anyone would be there but that's always cool.

-hitman maps: so this is gonna be a bit weird and beyond map making but screw it, just listing everything. so why not add highly populated maps of both civilians and aliens, sort of like maps from the hitman franchise. imagine a massive crowd listening to music and having combat start and everything breaking out into chaos (though actually writing it does seem a bit insensitive, and imagine the lag that would come from every NPC taking turns moving).

those are the first few that come to mind, have fun