As someone with a Ranger/Monk/Rogue high AC build, and someone with a 60 standing AC S&B build; I gotta say I agree with the sentiment of the OP.
I really like the insight " fix ". It works, it makes sense, and combined with tempest AC bonus going to a shield bonus, it should alleviate a LOT of the problem of putting S&B AC on par again.
That said; It's also only going to work if mob to-hit is readjusted for lower ACs across the board. If it simply puts them on par with the AC a S&B can achieve, and that AC still = getting torn to shreds, then you're going to have an outcry such as the forums have never seen before. And that would be bad devs; Very, VERY bad for the game right now.