I've seen Playful Darkness get mentioned here a couple of times - in Owlcat's defense, I'll say he's actually doable without having to resort to specific spells or Touch AC (at least on Core - haven't gotten to him on my current Unfair yet).
Hitting his 68 AC is almost like a pop quiz on the resources you have available to you and how to stack them all.
It's a fun game but Playful Darkness is a synodoche of the decisions owl cat has made. As you've said the AI is pretty dumb and he'll just hit whatever is closest so to deal with this they pumped up the armor class.
<edition warrior mode activated>
This is one the many reasons I like 2nd ed better. -10 AC is the limit you can't go any lower. (I know ToB did and they shouldn't have)
Many of the gods had armor classes around -8 or -9. In 2nd ed terms Playful Darkness has an armor class of -48 meaning it can only be hit on a natural 20. Luckily the weighted dice give you natural 20s more often than you guess but it's just a parody AC. It's tougher than any of the bosses in ToB-Ascension.
On mages in 3.5
3.5 did more than removing mage's ability to avoid all damage, it made spell failure a common occurrence. In 3.5 your mage can only operate like 1,2 or 5th edition mage about level 12 or so. They have a heavy feat tax. Go for that interesting feat instead of combat casting? Expect to be hit by arrows every time you start a spell. Want that spell to land? Why didn't you choose the spell penetration feat? Want a touch attach to land? Should probably take a "I can actually hit something" feat for or add another class. Mages don't get fun feats, they get feats that undo the nerfing that the 3.5 authors imposed on them.
This is my first time trying Pathfinder and does seem like they have un-nerfed spellcasters a great deal. Now with the abundant casting feat I'm actually having fun with a 3.75 caster.
But the game was designed for l33t gamers, it's a showcase for their mad skills. It's fun but the bloated stats will limit its audience and keep from becoming a classic.
