Agree on basically all of this
Also it is better to do hearts as you naturally get to them with the purifier line so you can take advantage of the space they clear.
the spread is already so fast it doesnt matter much if it is faster. You have enough time to shave a little corner at the start of a wave or if people are working together a nice little corner, but more likely than not you are going to need to purifier most spaces
I wonder if letting the corruption stack past 3 would make it more dynamic/group based or if it would just make some waves impossible after a period of low participation.
I'd kind of prefer that, but it could get out of hand.
ofc, if it gets out of hand, that just opens the door for new cool powerful solutions as you lvl up
I think I say try letting the corruption stack a Lot higher than 3