While I think 100% trapavoid is kind of cheesy, traps are the mainstay of guerrilla combat which seems very dwarfy to me, [trAPAVOID] is the lesser of two evils. I used to use the orc mod with trapavoid turned off, three base quality glass spiked balls ran off a siege. Yea, they're that overpowered.
Just had my first prepared encounter with the orcs, and they aren't that bad. Ran them off with some caravan guards, two legendary wrestlers/competent hammerdwarves in bronze, and two marksdwarves. Should be much easier after I get some immigrants - this siege came in the first friggin fall! Even the orc mod isn't that fast paced, if I hadn't planned on training a military, the fort would have been lost. Kind of scary, really, I like it.