1) It's nice that the structure doesn't break, but because it's still knockback reduction, you're able to be pushed out of range of doing anything useful with the structure. Usually you can get a straight, a struppercut, but it'd be nice if you were closer after it hit so you could more reliably use it as if you summoned it. Basically, make it so there's almost no knockback at all while guarding.

2) -1 damage is great against discs, but is basically pointless against stronger structures, especially since those are the ones pushing you out of proper retaliation range. I propose guard to halve the incoming damage, rounded down. It doesn't make you immune to structures above discs, but properly reduces the damage of everything else so you're being guarded effectively.