I agree. I think he already has elevated the talent around him.
But IMO there are two things Tua needs for success. He needs skill players who can do their job, but he also needs adequate preparation (at least until his experience level increases). I see that as the difference in the games he played well in vs. the ones he struggled in. Gailey even admitted that he had thrown out his notes on DCs when he retired so he had to rely on his assistants opinions about what to expect from the defenses. Tua is a fast learner. As Dilfer called him, "a one rep guy", but he needs to have seen something to learn it. Otherwise you'll see that hesitation and lack of shots that we saw in some games. Eventually, (usually after about 3 starting seasons) a QB has seen most things or something close enough so they can draw on their own experience.
So, yes improving what was often the worst skill position support in the league is a huge key, but the OC we bring in will have a huge impact as well.