Unless they normalize crit chance to be considerably more frequent and hit for considerably less damage they should remove the mechanic alltogether. To be perfectly honest I'm not a big fan of being on the recieving end of a critical strike that, under normal circumstances, would have grazed my unit, especially when the chance of it occuring is probably under 20%.
Dexterity isn't worthless because damage-wise it is worse than strength. It is worthless because it's not something you can plan for. You could go 4 battles in a row before actually getting a critical hit, or get 2 in a single fight.
My recommended Stat Changes:
Strength: Affects Melee Damage and HP
Dexterity: Affects Ranged Damage and Dodge
Constitution: Affects Hp and Defense (including elemental)
Intelligence: Affects Spell/Wand Damage and Resistance checks (no more bonus xp)