Bob's adds new more powerful bugs. I also use Natural Evolution somethingorother that makes their expansion/aggression AI tougher. Also Swarm, which makes medium/larger bugs split into smaller bugs, and all bug bases spawn bugs.
Ultimately though, once you unlock power armor mk2 or 3 or so, the shields are near impenetrable (fusion reactor is seriously OP), and the personal laser systems are absurd. I think it'd be relatively balanced with a serious nerfing of the fusion reactors.
TLDR: bob's, natural evolution, and swarm will all combine to enhance the bugs