I have seen very fast (8+ath) agi shielders like Malaclypse and Kartofflen get kited and shot by archers. I've consistently seen agi/balanced 2hs more successful with their great reach and speed. Even if you're in cloth, the shield ways too much and you move slowly regardless when you block.
Very high shield skill should lower shield encumbrance or provide a better dash effect while shielding and running forward like we have now when we don't hold block (with the same cancelling inputs). At the same time, lower the arrow weight to something a bit more reasonable. Agi shielders aren't good enough at offensively pressuring archers imo, and the prevalence of shields on the ground decreases the usefulness of shield skill. Even with this change, a melee hybrid archer could still give a lightly armored agi shielder some pressure, since any hit will be highly damaging.
Strength shielders like me should only be able to defend ourselves from archers, while the agility shielders should be able to chase them. Right now, we're in some crappy middleground where everything is just slow, and it's actually easiest for cav with shields to kill them at the cost of some horse health.