I don't think there is much to gain from separating to hit and to damage. We have other gaming systems that have done so and I totally fail to see any increased realism in their combat.
I had this problem when we tried to play Hollow Earth Expedition. They combine the attack numbers with the damage numbers to boil it down to a single check against the combined avoidance numbers and toughness defense numbers. It became D&D. There was no way to reflect a guy who is slow and/or uncoordinated but strong with a big weapon from a fast and accurate guy with a sewing needle! Of course, that is a bit of an extreme example, but that is how the game did it, and it felt horrible!! I COULD NOT PLAY IT ANYMORE WITHOUT MUCH ALTERATION TO THE RULES. Seriously. Tasted that bad. I guess the new World of Darkness works the same way, which is probably the biggest reason I haven't even tried to sit down and put together a WoD campaign - even though I love some of their settings (not the
new Vampire, Werewolf, or Mage - just the main WoD stuff).
The ability to reflect differences in the varous aspects of accomplishing tasks, and this goes for things other than combat as well, is something I care about greatly. I want to know that even though I may not hit very often, my immensly strong, half-giant, warrior will do some serious damage when he does. JMO.
Too much abstracting gets to be too much unrealism (or surrealism, if you will) and makes play much harder - for me at least. My tactical capabilities run to the "natural" not the rules dependant, which is why I am not good at miniatures games and the like.
The net result in my experience seem to be that the combat system becomes harder to model so you get more glitches when one type of attack is strangely better than another.
First of all: You are always going to get glitches and ways in which Power Gamers will try to get the maximum bonus or the minimum cost. That's going to happen. It is something that every individual GM is going to have to deal with in their own way (see the thread on Marauding Psychopaths for an extreme example). So long as every GM is capable of making individual judgement calls at their table (and they will until WotC, gains the ability to actually reach into our homes and control us as we game so that we dare not mess with their holy rules......sorry, personal issue coming out there.....back to the regularly scheduled rant) is not only impossible, it is uneccessary. Just get close as you can. BTW: Some attacks
are better than others, hence the constant evolution of weapons, armor, & tactics.