Fact is there is not just ONE evil playthrough there are 4 (Demon, Lich, Worm that Walks, Devil) as there are 3 good ones (Angel, Gold Dragon, Azata) and 3 neutral ones (Aeon, Trickster, Legend). Most of these give you different things to do in game and radically different outcomes, some stuff that is possible has never been included into a CRrpg (to my knowledge at least), and you get to do suitably epic stuff (in the angel path it felt really great to be able to kill Deskari once and for all for example). On top of this there is a secret ending (like there is one in P:KM btw) you can only achieve if you do things in a certain way.
It's not only the ending but also how you get there that I find important in a game. I have tried the gold dragon for example. Not only was it mechanically even buggier than trickster (which had several mythic feats not working), the transformation turned my entire character model an unappealing shade of brown, there was barely any content and my character's supposed mythic allies abandoned her. Same as the gold dragon will refuse to help you if you don't turn into one. Do the good factions even care about defeating demons? Doesn't seems so to me.
As for the secret ending, unless they overhaul the crusade system, I have no interest in that one. Because I didn't mind the kingdom management in PK, but the army battles in WotR are an exercise in boredom.
The reality is that there are noticeable differences in quality between the various mythic paths, in both the amount of bugs and the quest content. It's clear that the game was rushed.
You are entitled to your opinion I guess, but the major bugs were stomped out in the first weeks after release (much quicker than it happened with Kingmaker btw), and the game is now fully playable. The crusade system is not perfect (it's actually really easy if you know what you are doing btw) but I don't think it's terrible either, and personally I enjoyed the kingdom management aspect of Kingmaker, although how to do things was not explained well upon release. I spent 20 minutes learning how things were done though and everything went fine, the crusade system is much easier than that (and it's not necessarily a good thing).
