The Rogue classes have backstab instant teleport (and there are other abilities that allow you to instantly close the gap), your run of the mill melee class should be pumping points into health, and grabbing the best armor anyways, they should be extremely tanky in both armor and magic armor, with casters not needing more than a little physical armor, and a reasonably high amount of magic armor (to resist stuns, and to block most things that would be heading at them, mainly spells).
As for environments, they largely become irrelevant once you get bless, then you just bless everything and it heals instead. Drop some fire on your feet, bless it, bam time to heal with a Heal over Time Effect on me.
