Gish, Fax, not warrior melee. We are now contemplating warrior melee builds, and a gish build isn't quite what we are talking about. Still, nice try. Every build can be played effectively if you learn a few tricks, as evident in the "let's make the worst build" (or however it was called) thread, where they pretty much failed.
It's worth noting that even Fax's monstrous melee gish would probably have been even more monstrous with dual wielding. Two ravagers are better than one by something like 28 damage. Don't know what the damage numbers on that tome were, but I bet a second ravager would still have given at least 15 points more damage. Also, I agree with the premise that DoD needs more varied Warrior class skills. There's way more wizard skills than warrior ones, that's part of where the bottleneck lies. On top of that, several of the warrior skills do the same things in slightly different ways. Even mods tend to introduce wizard or rogue skills more than warrior skills.
In fairness there's always Werediggle and Vegan for different flavors of melee character, but they're both so drastically different that they tend to define builds to a much greater degree than any of the stock melee skills. They also provide huge bonuses to throwing, so they don't really encourage a pure melee playstyle--especially Werediggle, which exacerbates the limited selection of melee skills by being largely incompatible with half of them.
Well, a Universal Principles is worth 12 damage and a stun proc - is that worth more than ~1.3xing your damage?
I would say the stun proc makes it a yes, but I tend to gish instead of warrior, so my mage's circle proc tends to hurt more.
It depends. If you plan beforehand, you can switch it for a mirror shield before opening the zoo and use that additional magic resist to do something about caster monsters. Or you could just [you can insert a multitude of other possible solutions there]. And technically, no, it is not worth it. Dual wielding characters have the highest power output for melee characters, and unarmed characters are able to switch resistances at will, which gives them flexibility. Meanwhile, guys with one pointy stick and one not-pointy not-stick are the middling ones; they are best used for either gish builds or ranged builds, since ranged/magic skills will provide it with necessary power/flexibility. Or course, if the RNG likes you, it's possible to play a melee build that is neither unarmed nor dual wielding well, and an experienced player without an extreme bad luck streak will be able to do the same.