Kill the HP system and move to a minion like system. Same could be applied to players if wanted - could be brutal.
Players fight: ( I am making the ranks and hits up on the fly)
Minions - 1 hit and its dead
Sub leaders - 2 hits and they are dead
Leaders - 3 hits and they are dead
Sub Commanders - 4 Hits
Commanders - 5 Hits
Bosses - 6+ hits
Rather then focusing on damage you focus on attacks landing.
I suppose one could develop a formula based on (Total monster HP)/(Average party [W] value) to determine how many [W] hits it takes to drop a given opponent. In such a system, however, you'd probably want to count a critical hit as 2 hits. However, this, too will remove a lot of the flavor from various powers - particularly those that grant a boost to damage.
Instead of using a set number of hits, perhaps eliminating damage rolls in favor of fixed damage would be a better option? Any non-critical damage dice would do average damage. Crits would remain unchanged at maximum [W]. Ferinstance:
A dagger-wielding Rogue attacks with Combat Advantage and lands a Sly Flourish. Normal damage generally looks like 1[W]
|let's call it 4+3, or 7|
|minimum value + maximum value|
|Average result on a d6 is 3.5; remember to drop fractions at the end of your calculations!|