The archer seems to be pointless.

[Splurd]

those are some pretty terrible archers you are not choosing lol.

not to mention the massive of health / mana pots those warriors will be using

5 archers is a bundle of dps and crowd control (root / repulse shot/ even kiting)
i usually run with 2 other archers and thats enough dps and control to clear an instance easily and quickly

At higher levels, warriors dont have hp potion problems, only mana potion problems. Their armour will be high enough to tank.