The rhaloren aren't that bad, really, as T4 factions go. I mean, they're not
good, and they've got heavy ties with the corruptors (which isn't,
quite, necessarily
bad, but it's not
good, either.), but they don't seem to be entirely terrible. The player ends up doing worse than they probably ever will, really.
Genocide of a sentient species is pretty hard to top, and even if you don't go that far, you're still forced to basically murder the best and brightest of the orcish people. S'other stuff, too, but that's the big one.
Highers aren't magic users, no, but they're touched by magic... which generally isn't the best of things, or at least has the potential to go south
All the extra-normal power sources in T4 have been shown to go tits-up pretty easily. At least stamina's stuck with normal violence and murder, heh.
The only ones that can go AM are EQ, stamina, hate, and psi users. If you've got access to any other resource before you hit the world map for the first time, you won't even be able to see Zigur, much less join.
Not that joining up with the Ziguranth is a sign of anything even remotely good. Genocidal racist/misogynist child torturers, they are, among other atrocities. Mind you, what they're nominally going against (magic users) aren't much better (Hey guys, let's break the world!), but th'Zig folks are pretty sickening. I'll take my reckless advance of power (mages, corruptors, etc) over them any day of th'week.
As long as I'm not doing a challenge run, anyway