I suppose you're right, but I'd much rather have players fighting by attempting to disable enemies in clever ways than numbers. It just seems better to me to have a fight go like this (slightly adapted example of an actual fight from an RPG I played):
"The creature lowers its head and charges at you."
"I aim for its head."
roll d20... 15!
You land 2 bolts of plasma right in the center of the creature's scalp. A thin layer of skin is burnt off, but the shots don't seem to have pierced the skull. The exposed bone gleams in the sunlight. It doesn't appear to be made of any organic material you've ever seen before. The creature continues to charge, seemingly unfazed.
"Alright, I roll to examine the creature as best I can as it comes at me."
roll d10... 7!
It's 8-legged, insectile (though with no apparent exo-skeleton), and about 7-8 feet long. It has an extremely wide, flat hammer-like head and thick, almost stone-like protrusions along the top of its body. They appear to be made of the same strange material as the exposed skull. Its legs are short and spaced relatively close together. In many ways it resembles a giant hammer-headed centipede. You think to yourself that creature like this with its skinny legs and massive, heavy body must surely be extremely unwieldy and not particularly agile.
"Can I fit under it?"
Yes.
"I wait for it to approach, then at the last minute, I quickly lie prone directly in front of it. I pull out my knife."
The centipede sees you lie down, and attempts to slow down realizing it can no longer hit you center-mass with its head. It fails, and is now skidding towards you, only a few feet from being directly on top of you.
"I anchor myself to the ground with one hand, and with the other stab upwards."
roll d20... 18!
Your knife parts through the fleshy underbelly of the creature with ease. You barely manage hold on as the creature slows and eventually stops. Your knife has torn a 3-foot gash right down the center. Strange alien viscera pours out of the wound. The creature lets out a strange noise, a mix of terrifyingly human-sounding screams and insectile clicks, spasms, and then collapses, dead.
In a numbers-based RPG, there would have to have been quite a few complex modifiers to allow for a knife to be a one-hit kill, even though the player in this case showed fairly impressive strategy to get himself into a position in which he could use the enemy's strength against it. The creature would've had fairy high health (say, 20) and the knife would be a fairly low-damage weapon.