The reason I have trouble with making shields better for dueling is how does that make it any better than manual blocking? If you use a crap shield and have low shield skill, of course it will break easily. Agi shielders already have highly durable shields (25+ hits for a non-shieldbreaker).
That's the problem. I'm often losing against players who are worse than me, just because I have a shield.
On my main those players can dream winning against me in most situations. Also, as I pointed out, if I put shield on my back and fight like "swashbuckler" I will win against those players.
How would your suggestion make it easier/more interesting to fight in duels when swashbuckling performs just fine? 1h without shield is actually pretty good in duels, anyways. It seems as though you need a timing similar to a chamber without any of the benefits. 1h has high chances of getting free hits if they chamber with overhead and sometimes left swing. If you tap block correctly, your shield takes less damage. The people good enough to do that reliably would probably just chamber or completely defeat those opponents anyways.
I'm actually regretting for putting points in shield skill. As swashbuckler, I would get shot a lot more but I know how to dodge. I'll be faster without shield and win most melee fights easily.
Even with shield, I get shot all the time, have to wear light armor to be moderately fast and so many hits go through my shield.
That's why, for me, it makes sense to have shields perform well against multiple opponents. You can do better in 1v1 without a shield typically, and dodging ranged can still be effective, yet 1h without shield can be a huge pain against multiple opponents. The longer weapons get stunned, while the shorter/heavier weapons can't reach anyone and you get easily surrounded.
Sometimes, it does feel like what you said, sometimes. With heater shields, you can still get hit over your shoulder or on your sides (arrow hitting from 30 degrees to your left/right) sometimes. With some of the round shields like elite cav, you are susceptible to getting hit on your legs. Minimum 3 shield skill is required for high tier shields like the brown lion heater. Even so, most shielders take at least 5 just for the sake of convenience for picking up all the viable shields off the ground. Adding any more is optional for how durable you want your shield to become.
It will be odd if shield was that beneficial with only a few points spent on them, right? High shield skill is a huge commitment, since those extra 3-4 points could go into ironflesh or weapon master. I'd rather have high shield skill buffed a little bit, since only the most dedicated like Matey or Eyebeat (as far as NA is concerned) I would imagine have it that high.