Again, it comes down to what kind of gameplay you want to emphasize.
You're looking at it simply from a roguelike's perspective. In that case, I do like knowing what I'm more proficient with so that I can use that weapon and have better chances of ... not dying:)
Imagine a MMORPG, where RolePlaying is actually meaningful in the context of the game (it is not simply an excuse for a hack'n'slash environment)... it makes sense to me that certain characters will want to re-inforce their "burliness" by using a warhammer instead of a sword (of realistic proportions). If both their stats are "very good", the player will, generally speaking, see no technical advantage in using either. He'll probably choose the warhammer for his stocky character - even though in your case, the sword would be deadlier.
Anyone seeing him wearing blacks, bearskin cloak, heavy (blackened) plate mail, chainlinks for "adornment" and such, along with his nice'n'heavy warhammer will think him a lot "cooler" than if he had a regular run-of-the-mill longsword at his belt.
This is just one of the limitless number of examples one could find where players start caring more about the actual roleplaying than about maximizing numbers. The underlying system can still be as technically complicated as you want, even equal to the roguelike's, but you've effectively changed the way the game is played - which was my original point.