There is still the whole matter of needing talent at basically every position. This announcement isn't as exciting as, say, that of a Cam Newton but it's still adding talent to a largely untalented team.
One, small, but significant correction. This recruit replaces talent more than he adds.
Again, you are directly correlating the results from guys on this team against future results by a new guy, that is now under a new coach in Snyder. And more importantly the guys on the team now in this comparison came through the RP system. There is no comparison.
The only that you should make is Snyder's results with Juco guys. Or if you like better, his results with wide receivers over 6'2" tall.
On paper, this guy's measureables are more than meh.
Is Snyder a miracle worker, one could argue yes. Will whomever he brings in get better and achieve their potential, yes, if they are willing to work and learn, then yes. What more can you ask of a HC?