I have no idea whether Drayton is doing a good job or not. Position coaches like that are so hard to judge to most folks outside the program.
However Texas has had OL issues and running problems for over a decade now. They started before Mack decided to switch to a more 'bama' type of offense in 2010. No one considering Texas right now has any memory of Texas being a rushing powerhouse. Jamaal Charles was a loooong time ago.
That's a pretty tough sell for a top RB looking for a program where he can run the ball.
Still, we have Ingram getting pre-season attention, and if he stays healthy could have a pretty good season. One of the things I'm looking forward to most this season is a return to a power OLine where Ehlinger isn't relied upon to carry the rushing load. Having our QB carry that load has been problem since Colt.
That's an incredibly difficult problem for a coach to fix, but we've seen signs that this is getting better under Herman and Drayton. We all want it to get better faster, but as long as we're seeing steady improvement then that's all we can ask.
I think if we get to a point where these issues are fixed, we're rushing the ball like nuts, but we *still* can't attract more 5* RB talent... then at that point it's easier to judge just the recruiting ability of your position coach. But until then both Herman and Drayton have a pretty tough sell to guys who didn't grow up already a Texas fan.