Breathtakingly innaccurate.
Firstly, we were GCD-capped before we had focus and we were GCD-capped after. Nothing changed there. (Although Legion made us not GCD capped, because Celestalon is a fucking moron)
Secondly, we had far more casted abilities when we had mana. Beast Mastery in BC literally did nothing but Steady Shot/Auto Shot. Marksman in WotLK used Steady Shot as a filler when waiting for cooldowns on Chimera Shot, Aimed Shot, and Arcane Shot (and eventually you would drop Arcane Shot from the rotation as well).
So where the hell are you coming from with "we spam steady shot now"? Steady shot was spammed just as much, if not more, when we had mana. Also, don't forget that we were far less mobile. Hunters before Cataclysm were far, far slower-paced.
Oh, and we really weren't that well distinguished from Casters.
Focus was a godsend.