So after running a few sessions using my alternate weapon system, I've gotten a sense of how it actually plays, and I've made a decision on whether or not to fully include it in the revised edition of E&E.
What I Like:
Modeling different weapons by varying the to-hit bonus rather than the damage die is awesome. For whatever reason, most weapons dealing 1d6 damage manages to feel more like D&D than the much commoner different-weapons-deal-different-dice system. So that's definitely sticking around. Plus, having a to-hit modifier being one of the inherent qualities of a weapon makes it easier to use Delta's Missile Modeling, which is the most realistic (but easy to use) system I know for handling archery.
What I Don't Like:
As much as I'd like to keep it around, having a parrying bonus to AC based on what weapon you wield makes AC too difficult to keep track of from round to round. Consider: I like to use simultaneous initiative, so everything all happens at once in a combat round. What would a character's parrying modifier be if they were throwing a dagger that round? Should they count as "holding a dagger" or "unarmed"? Problems like that tended to crop up more often than I expected. So the weapon-based parry modifier goes away.
I'm going to replace it with another mechanic to be tested, which I'm calling the parrying factor. Previously, whenever a character gave up moves or attacks in combat in order to defend, they could give themselves an AC bonus for that round ranging from 1 to 3, depending on how many moves or actions they gave up. I've decided to take this mechanic and alter it slightly, so that the AC bonus you get depends on what weapons or shields you carry, and it's just a static bonus based on that. You give up your attack and you get 1 to 5 points of AC bonus for one round, ranging from 1 point if you're totally unarmed up to 5 points for a character with (say) a great sword or a pole arm or a one-handed weapon with tower shield.
It's much, much simpler, far easier to keep track of (in fact you can track it with a d6 sitting on your character sheet), and it makes parrying back into an active choice, almost exactly the way it works in Holmes Basic, except for the varying AC bonus.
It remains to be seen whether 5 points of AC for the largest weapons and most defensive weapon–shield combos is too powerful, but I doubt it. For one thing, players are always reluctant to give up offensive action and the chance to deal out as much hp damage per round as they can manage. For another, I expect that the benefits of tanking on total defense will prove to be as highly situational as ever. (After all, one character attempting to block a door with a tower shield can still be overrun by the press of a large number of enemies.)
So What Will it Look Like?
Assuming this most recent system works out, a typical stat line for a weapon becomes the following:
Arming sword, Medium-Size, To-Hit Mod +0, Parry Factor 3
Long sword, Heavy, To-Hit Mod +2, Parry Factor 4
Long bow, Two-Handed Missile, To-Hit Mod +4, Range 90'
—To give examples of a one-handed weapon, a two-handed weapon, and a missile weapon. In all cases the 1d6 damage is implied, and there's a note in the rules that characters with missile weapons have the same parry factor as if unarmed (PF 1).
All in all, I like the look of this much better. It's cleaner, simpler, and it still mostly "gets it right"—even if it is sacrificing a lot of the realism I liked so much for a more abstract but smoother gameplay experience.