Shielders should have an advantage over 2h in very close range, which is not the case now. 2h can hiltslash from either side, whereas 1h can only hiltslash from the left. Thus, this shield bash mechanic should be slightly better than the kick mechanic. I propose same range and effect as a kick, except it blocks melee attacks from all four directions during the attack (2h and pole can block 3 directions during a kick). It should have some kind of cooldown though, as should normal kick.