It depends on the character, but I felt comfortable setting Dex to 8 - 10 for Druids and Priests and 3 for everyone else.
I still look more at the special abilities (and style ), but for the most part, yes, the heavier the better.
I would max PER, MIG, and INT, and then equalize DEX, CON, and RES.
I feel safe setting Wizards' DEX to 3 in turn based because you cast Fleet Feet as a free action to get more DEX and you can use Escape as a free action for getting around the battlefield. You may also want to consider Beguiler/Debonaire, Skald/Debonaire, and/or Tactician/Debonaire.
I ran Tactician/Priest of Magran for most of my PotD run, and I could basically nuke every turn. Blood Mage or Blood Mage/Berserker would also be good options. I'm generally not a huge fan of the specialist mages because I don't like being locked out of useful spells.
Dump it, homie. I generally want to go after the enemies, because I want them to gather around my tank so I can more efficiently AOE the crap out of them .