Yes true about the shields, however I would remove the health damage and instead just do stagger damage. I don’t think the health damage makes block too appealing. Sure it might be actually decent, but I think most people will not like using shields because losing health for blocking feels bad. I would also argue that is not favorable in a game where healing is a scarce resource and not being hit is better than losing some hp.
Actively blocking is a conscious decision more often than a reactive decision so i think it should be punished through over-zealousness (blocking too much and getting staggered for big damage) rather than chipping at your health.