Shielders are probably the only melee class that still needs high AGI to be viable. Sure, you can be fancy and effective against lightly armored/peasant enemies with a balanced/agi build, but when people are running around in heavy armor, even mediocre players with FULL STR builds tend to top scoreboards, simply cause they can take half a dozen or more heavy hits from a hard hitting 2h or polearm, whilst killing non-str builds in 1-3 hits reliably with anything.