[@Knox]
I had considered insectoid monsters during my original design phase, and like you suggested thought about making them some kind of "trap master" type of character. But the most common abilities for most insects involving paralyzing or poisonous stings, fangs, etc. which the Fanged Lizard already does. Building traps out of webbing, or digging out pitfalls in the ground, could be an interesting form of combat but it seemed like it would force the players to be too passive--they build the trap, then sit and wait for something to fall into it, and I didn't think players would enjoy waiting around like that. Being speedster types, using guerrilla tactics, could work but then they would be another form of DPS like the Dire Rat, and I tried to avoid having the starter monster roles overlap as much as possible. 

Not to mention most "mook level" insects would be things like giant ants, or *Projared voice* BEES, and these creatures are hive-minds controlled by a Queen. Players already have to stand out among their monstrous peers to survive, but when doing so goes against the nature of the monster itself it just seemed like it wouldn't work out.

By all means though let's hear some more thoughts on the subject, maybe someone can help fix the issues I've pointed out.

[@King Cosmos][@Gobby]
The thing about becoming Undead is that one has to [color=red]die[/color] first. ;)

I actually decided on that as a sort of "mercy" system just in case--if a player gets in over their heads and bites the big one for a second time, they immediately get the choice of becoming certain types of Undead. But a Zombie has to have a body, and a Ghost has nothing left if it gets destroyed again, and of course the Demon King won't be so kind as to reincarnate you a third time...