I wasn't sure if you are accepting suggestions, so if you aren't go ahead and close this. Otherwise, I have some ideas for behaviors that spiders could possibly posses in addition to their improved pathfinding:

• spiders can "swim" in cobwebs similar to how drowned swim in water.

• spiders will shoot webs at the player if the player is faster than them. this takes the form of a projectile that encases the player in webs on impact, or just places a web block on impact with blocks. Webs will decay if doMobGreifing is set to false.

• spiders now sometimes spawn with "spider nests" in overworld forests, with cocoon blocks providing loot. these nests are similar to the ones in mineshafts with cave spiders and contain a central spawner.

• if a spider can't reach the player, but the player is in web range, the spider will shoot webs repeatedly until a bridge of webbing is formed.

• cave spiders will attempt to crawl on ceilings and drop on top of the player.

A spider nest

Thats fair.

Yeah, I'm not sure yet whether I want to keep the mod as simple as it is now or actually add new significant features like this.