[Zechnophobe]

If you really like no retal, try Royal Snakes. They are incredibly good. Compare their HP to their Leadership some time. They also have super high initiative and a great item that gives them even more. They don't backstab like Assassin's, but you can Stone Skin them, or Bless them, and their ability to strike from two tiles away lets you put your 'tank' in between afterwards.

Oh, and as for Warrior, you will have shorter and more brutal combats. Since your stacks should be ripping the enemy ones to pieces, high initiative, high movement units can do wonders, since they'll get to do their damage fast and early. Combine, of course, with Tactics to make sure the enemy doesn't survive the first turn well. A starting Fiery Phantoms in the fight goes great for this. Use spells that don't need high intellect, such as Blind, Slow, Target, Timeback, stoneskin and Phantom. (Phantom DOES use intellect, but your larger stack sizes off set this).