The full WP/VP system from Star Wars is deadly in D&D:
1) a character has about a 5% chance of begin killed every round by every monster at higher levels (natural 20 ... then the 1st attack of monsters usually hits anyway, and usually a monster does at least 20 damage, that is enough)
2) A fighter with keen rapier/improved critical and all those combos to get to crit about half of the time will kill almost everything in 2-3 hits (say Str 20, +3 weapon is about 11 WP damage every critical!)
And, there is an additional side effect:
at low levels, a Kobold and an Orc cannot be brough down by an average sword blow, but they will remain up and so they can attack more times:
consider an Orc vs a 1st level PC.
if the orc hits, it's 1d12+3 = about 9.5 damage. Two hits and you're dead. And he's also got a good chance hitting low armored foes (+2 vs an AC of 15 is about 40%).
But the orc is a simple CR 1/2 because it has only 4hp (less than a longsword blow with no str bonus). But if it had 14 WP/4VP it can be scary (three hits bring down an average Con fighter).
And so the results could probably be
- lots of armor/protective devices to prevent being hit
- lots of keen weapons, improved critical and high treat weapons (against a monster with Con 30 and 300hp only the critical hits are useful)
- more ranged combat / reach weapons: if the combat is deadlier, who strikes first has a better chance of winning
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Maybe you could try a softer version. on a critical hit apply the normal VP damage multiplied by the critical, and apply the critical multiplier as WP damage. so a weapon with Crit 19-20/x2 does 2 WP damage on a critical hit
And you might remove the "cannot run or charge" penalty for exhausted characters (to be a bit more heroic)
Also, remember to give a lot more WP to nasty beasts (multiplying by size)
