Can you implement a fix that marks a path to what the biters attack before they become valid? islands off shore of my base arecausing my fps/ups to drop to the single digits and i have to spam killl all to even play.. concrete out there just pushes them farther out. i have half my base on a continent thats still biter populated and they dont spawn there either.

I haven't run into any problems like this, and I don't want to put out a half-baked release that might not fix it, but I do have an idea. If you're willing to try hacking a bit on your side, try this. In data-updates.lua, between lines 4 and 5, add this line...
dummy.collision_box = {{-8,-8},{8,8}}
This will cause the mod to search for a clear 16x16 area to spawn new groups in. It should prevent too many groups from spawning on any single island.

I don't want to implement a fix that checks for a path before every spawn, because that will double the amount of time spent on pathfinding.