Wow Hangman, you have put quite a lot of thought into this. I am presuming that you are using this in your game. How is it working for you? I actually run my games using AD&D second edition (2E), so I am not up on the older version (especially since I don't have the books for it). It seems like there is quite a bit of figuring that has to be calculated, but then without actually using it, I cant' really say if slows the game down or not. I will take your word on that since you have experience in using this house rule mechanic.
I do like the idea of lighter weapons are able to make more attacks than heavier ones. Do you have something in place that will allow a character with a very high strength to have the extra attack bonus with heavier weapons since they are able to swing those weapons easier than most other characters can?
When you say that the minimum Weapon Speed Factor is 2, am I correct in presuming that is before any adjustments due to racial abilities and stat (strength, dexterity, etc.) bonuses? I ask this due to the fact that in our group, we have a Dwarf Wayfinder that with a good die roll, he can have an initative that is a negative number.
If a character would get more than one attack on their turn, does a miss on the first swing end the attack or does the character still get to make the second (or more) swing(s)? I have had this happen in our game. My Dwarf Fighter gets 2 attacks on the even number turns. Have had sometimes where the first swing missed but the second swing hit. Our explanation for this is that the opponent was able to dodge the first swing but isn't able to get out of the way of the second.
I look forward to read your reply.