My current suspicion is that with the current system, STR does not actually directly modify attack, it folds into the damage calculations somewhere else.

Which, yes, makes it harder to see how much of a difference your gear makes, and I haven't done anything -remotely- close to actual testing on this hypothesis, so take it with a grain of salt.

I've definitely noticed loading up on STR making a difference in my damage numbers without modifying my Attack score, though, for what it's worth.

Anyone have any hard data here or number crunching that's already been performed?