Sado said:
Well, neither has greater than a 5-ft reach according to the rules. If the dagger guy had higher initiative than Sir Greatsword he would get to attack first. Just as unrealistic.
I don't mean Reach in the DnD sense. I'm talking in the context of "realism". Your post implies that you think giving a dagger a speed advantage over a greatsword would be more "realistic" because the dagger is lighter. If this works for you fine, but it's not more "realistic" since DnD already simplifies combat so much.
Think of two boxers. One is 6'2" and the other 5'5". In DnD they'd have no differences, but in RL, the former would have a significant advantage from the length of his arms. Greatswords etc. would be similar I think. Yeah, the dagger might be slightly quicker, but an extra foot or two of reach is a big advantage. So if you really want "realism" then the greatsword should be attacking first all of the time.
If you don't want realism, then why add this complexity? DnD rules simplify combat to avoid worrying about reach (except in extreme cases, ie polearms), this difference between daggers and greatswords is already overlooked, but I see no reason to give daggers more of an advantage. Math is BAD, why would I want to have to do more of it?
Changing weapons can change BAB, range, damage, why not initiative? Take the guy's current initiative count and modify it according to the new weapon.
Not to be pedantic, but weapons don't affect one's BAB, they can affect one's Attack Bonus though.
Other posters have responded to the other issues you raised here, but hey, if you want weapons to grant an init bonus, go for it.
