More bugs would be cool. But we need the fence to bust open somewhere opening another yard with new ecosystems. Hopefully a rundown house that can be fully explorable. Maybe use pipes inside the walls to go upstairs. Maybe a rat boss in the kitchen. Use rotten food to summon. Old pet tarantula or scorpion loose somewhere as a random boss/Hazzard. Some daddy long legs here and there. Maybe an underground base building area. Trapdoor spiders possibly hiding entrances to random loot chests. Like in the middle of the basement leaving room for attacks from all sides. Maybe a grasshopper mutation allowing for higher jumping. Maybe a new bubble gum arrow that forces flying bugs to land for a moment allowing for a quick melee attack. Allow new buildings with lab equipment and electronics. Some more weather would be cool. Maybe once in awhile it rains and floods some sections temporally.

Busting open a fence would be amazing to expand the yard, and an "Under House" Biome, after the under shed was so terrifyingly brilliant. House Spiders... *Shudder*