You are honestly going to sit here and say that 'proper booking' would have covered up Ryback's terrible lack of talent? for how long? Until he kills someone in the ring? Until he puts on the shittiest main event matches in recent memory? Too late on the latter, probably close to it happening on the former.
Since when has in-ring quality meant anything? I've already said that I never found his ring work all that bothersome, personally. There's probably several others who would agree. Ultimate Warrior sucked dick in the ring too but it didn't affect his overness. Anyone who knows anything about wrestling should know that people here in the States typically don't care about ring work as long as you have other positive qualities to make up for it.
As far as cutting promos go, they could have worked around that. A kind of "play up his strengths, hide his weaknesses" deal. There's other talent that got over despite not being worth a shit on the mic either. Just keep Ryback as the man who says few words while still encouraging him to keep honing his mic skills in real life.
Obviously if he's hurt people in the ring for real and has the rep of generally being an unsafe worker, then that's gonna hinder any sort of real push he might get but if he were really THAT dangerous to work with, there would have been enough people who would have complained to the point where he'd be removed from the main roster and sent back down to development until he learned how to work without injuring people.