I find the biggest problem with blocking is just how much distance gets put between you and whoever hit you. I'd LIKE to do spear + tower shield and go all Greek on the enemies, but between your own pushback and the attacker reeling, you're like 2 spear thrusts away from them after every swing, which is completely useless.

I pretty much parry exclusively. That's partly because of the above problem, but partly because there's really no reason to block OVER parry. Parry is the skillshot that nets you better rewards at no additional cost, it's meant to be superior but requires more effort.