I read this old school blog called Grognardia, I like it, the author has some good content and his writings about his campaign and what he likes about certain game systems is what originally made me kind of fall in love with Labyrinth Lord and some of the concepts behind old school gaming.
Recently, he wrote a post about two-weapon fighting vs. the use of shields. His thought was that two-weapon fighting is way too impractical for anyone but the most skilled combatants to use, and a measly +2 bonus to AC can't really compete with it the in game benefits for doing so. Even in Pathfinder, with half your Strength bonus to your off hand damage, and the -2 penalty to attack rolls, having bonus attacks is definitely superior to a small AC bonus. You can also take a feat that grants you a shield bonus to AC when you wield two weapons.
With Pathfinder you can use a shield and go the two-weapon fighting route and do shield slams and that kind of thing, but just a straight buckler and sword can't truly compete with how handy two-weapon fighting is, other than in terms of prerequisites for the feat and how many feats it takes to get awesome at using two weapons. It takes quite a few feats to get the attacks and shield bonus from two-weapon fighting, with a shield, you just wear it, I believe there is also a feat you can take that gives a bonus to AC.
Eventually he comes to the idea of your shield bonus to AC being based on Strength. I really like that idea, I'm just wondering how practical/useful it would be to implement in my Pathfinder game. Perhaps something along the lines of half your Strength bonus to AC with a buckler, and then half your Strength bonus plus one or two as you move up the line of bigger and better shields. The thing is, Pathfinder/DnD combat is so abstract, I'm not sure a rule like this is remotely necessary. So what if shields are super useful? Combat is super fucking abstracted in this game. I've met players that believe your attacks per round are how many attacks you make in a six second round and your hit points are an actual measure of how many stab wounds you can suffer. Neither of those is accurate. I guess this is a moot point really, no one in my current group uses shields. Of the two weapon based combatants (we have a monk and a bunch or sorcerers other than these two) Jeremy's guy dual wields revolvers and John's dual wields rapier.
Thinking back, I vaguely recall Mutants and Masterminds having a system of health and dying that I really liked. I wouldn't call it more realistic or less abstract, but I like it more than hit points. The gist of it was that if you take a hit of a certain power level, you made a Fortitude save, failure weakened you, success meant you were tough and shrugged it off. As you failed saves you became progressively more fatigued and staggered and eventually passed out or died. For some reason, I always fancied that set up.
I don't know that I'm prepared to make a ruling on the shield issue. As I said, it is pretty irrelevant in my game. However, I think I would like to reduce the Dexterity requirements for Two-Weapon Fighting feats. The requirements are high, I believe a nineteen in Dexterity and a +11 base attack bonus to take the feat that give you your third off-hand attack. I'm not sure, I guess. I think that perhaps I need to think on this issue a little bit more before I make a decision, this is more of an exploratory post I guess. We'll see.