You don't need to *slide* around. In another game they animated upper/lower body separately. so you could run around, and upper body would rotate, and attack; lower body would run. If you stand still and attack it's the normal animation.

I don't want animation-lock, cause it's just annoying being rooted for the duration of an attack; Maybe for some skills it would be ok, but in general no.
I think the GCD is ok. I think it will be somewhat of an non-issue at higher lv.