This is why I think there should be very few hearts towards the middle of the game and more on the outskirts. These guys already have the middle and are making bank, they then can collect all the hearts they want and harass the people on the outskirts with no extra investment. I think it should be the other way around.. You are getting all those coins you don't need all those hearts... at least pay for some characters. Give newbies a chance without very much extra investment.
These guys are moving into the red area at the moment. Can't really do much except run away.

The other element to this is its been a while for a disaster so characters have had a lot of time to really build up. I have has a few that are maxed out also by just picking them up on the outskirts. Some of it is luck. So at least in a few days everything will reset again, but I imagine the end result will be the same for this disaster cycle again... Hopefully things will change.
I still think the best change mentioned right now is limiting the number of coins per player to 100 or 200. This greatly influences into trying to seize large number of coins, ambushing, and the disaster rush.
After losing their big chunks to the last couple of disasters, I suspect the "group" will be waiting to move a lot of coins during the 1 day safe disaster period coming up. Maybe there will be 100s of players waiting to ambush them!!
Yes I think 100-200 is a good number (150?).