The challenge level the 1hand fighters experience feel disproportionate to the 2handers. I don't care what anyone claims, you only have to look around battlefields to see it. The people getting kills consistently and climbing the scoreboards are almost always ranged and/or using 2handers/polearms. There are less and less 1h/shielders around, and they're tending to be meat shields for the people getting the kills.
2handers mostly have heavy armor, and I have to hit 4-7 times to kill on average. Many fights with 2hand users I'm dead after just 1 hit from their weapon. I have 4 IF, 4 PS, Side Sword, Studded Leather Coat, 116 wpf, 16 agi and 14 str. I get kills, I just have to work a lot harder than a 2hander to get them. Because of the shield lag issue, I have to wait for people to screw up either on their timing or on their footwork to have a ~chance~ to get an attack in. Then that has to happen several times per person. It's not that I can't parry, but when you have to worry about parrying 4+ times and riposte successfully every time, it just not always worth it. All you have to do is screw up once and you're dead, whereas they can go nuts and make mistakes.
Most 2hand players I see hesitate only if I un-equip my shield. Shields are not supposed to just be arrow stoppers. The defense they provide in melee is supposed to aid the wielder's offense: by deflecting weapons away when blocking, and because you can smash them into a face to disorient. That's why many shields are rounded and not just flat. If you don't understand the distribution of forces against angles or curves, then go learn some physics.
A realistic example of what I'm talking about: Knight with greatsword fights a shield and sword fighter on a rampart. Knight swings and misses, hitting into the rampart wall. The shield fighter hops back into range as this happens to trap the greatsword against the wall with his shield, and exposes the knight to the 1hand sword which is still free for the swinging or stabbing.
Another example: Shield blocking an overhead attack from a 2hander up high before it comes down, leaves the 2hander's torso exposed to an underhand stab, since only the shield arm has to go up high for the block, not the weapon waiting in the other hand.
Anyway, the point is that shields shouldn't stop you from using your other arm in coordination. The shield-attack lag phenomenon is unnatural to non-huge shields, and people with 2 arms.