I really like the Sectors one. Something about having choke points speaks to future scenarios with more tactics etc. Like maybe the Corruption builds against a shield until it breaks through if the shield isnt reinforced.
The boss one is pretty fun too! It is rough having to wait for 3 players to do dmg, but it is a nice way to make sure 1 or 2 ppl arent pushing the waves real high when we should be losing (which I am guilty of lol). Which balances nicely with the slowing of lost waves when no/few defenders are active
the one with the triangle grid to set up. . . . well, that one needs work. The grid doesnt actually do anything except make some super thin lines the corruption cant cross. You end up justs going from corner to corner across the map anyway and it doesnt matter at all if you set up the grid or not before the end.
Maybe if it started clearing the inside after fully activated, at least it would save some spaces to be cleared, but as it stands it is not really meeting its goals. Though I do like the idea behind it. It could combine with the chokepoint and more intricate maps to create some cool dynamic battlegrounds later.
Since we have an overhead view, maybe we are managers instead of boots on the ground and get to deploy teams instead of purifiers. then our moves are based around supporting and placing our limited number of clear teams, working with other manager's clear teams and setting up shields etc. to support them while the Corruption wears down the shields to break into our op area and/or infect our teams (maybe corrupted teams spread infection instead of clear it.
That may be moving toward a completely different game than your vision though, just dropping seeds to open doors of thought.
Cheers!!!