He's done a decent job at stabilising that basket case of a club in Glasgow. But managing in Scotland can't be ever an indicator of quality management, sad to say. Beyond Rangers, Gerrard would have to test himself in England before we could even squeak the merest mention of him becoming manager of Liverpool.
And to do so he'd have to do something remarkable because the next manager of Liverpool (and the manager after that, and the one after that) will have to be one who has shown he can do something like Jürgen did at Dortmund. Klopp has set the standard for future appointments so so high that to abandon such standards in favour of sentiment would be cult like bordering on suicidal. It's just a non-starter for me I'm afraid.