Another thread talked about the danger of 1-Dex zombies lying in the sheer volume of them: I know this isn't a map/grid game, but should there be a limit to how many attack a single target each round (for the support bonus die)? My first thought was 3-4, but then I thought about a grid and diagonal attacks - so maybe 8 if they're fully surrounded. Then I thought about how zombies are mobs that crawl over each other in an effort to claw their way to the target...so more?

I'm not sure.

The grid-combat tactician in me limits it to 8, which is a max of +7 dice for 7 possible Assissts.

Remember this will be useable by the PCs too, so if you have a group of 6... yea, single foes are gonna be boned.