Fatigue is indeed a slight issue, but I never see more then 50 to 60 listed there.
200 or so Archers will make sure the fights last rather short
Never gotten to play a Thri Kreen, but they do have a few mitigating points to those 4 arms:
You'll be paying 3 to 5 class levels depending on the version, depending on your class choice that's not always a good idea.
Also, these bugs only have a relatively short lifespan. 29 years at most before they drop dead. And I'm certain there is at least one spell around that raises a target's age permanently.
A Thri Kreen Ghoul on the other hand....
But that's a bit of topic, not unlike your own post Omnirizon.
Edi, unless Middle and Late Age Arco(whatever nation that is) has access to a Nataraja, I doubt your suggestion would work. As I mentioned in the first post, I've only seen this guy on EARLY Age T'ien Chi, Caelum and Kailasa.
I must admit, it's a tactic one can certainly try with a guy like this.