Nolan needs to play another 50 games of football before he can really be properly assessed. With the injuries he's had, he just hasn't had the development that you'd expect.
It's a real shame that we didn't get a chance to see Lang and O'Riordan as a settled partnership. Given a season to play together, I honestly think you could be looking at a standout Championship centre half pairing there.
I'm unashamedly a huge Lang fanboy. He made a couple of mistakes yesterday, but by and large he's a dominant force, and he knows when to step out of the defence and push on (something which Nolan, for example, just has 0% ability or compunction to do). It's also worth remembering that, like Vaughan, Lang hasn't had a pre-season and has been thrown into a scenario where he's having to (literally?) play every minute. I'd have him right at the top end of the list for contract extensions.