No doubt Arsenal are happy with Arteta now but they really dropped the ball letting Emery go.That's true and implies it's maybe the time to take a punt on an up-and-coming young manager because the opportunity cost is lower than usual (i.e. you aren't overlooking some obvious big candidate to appoint them).
Someone like Emery is probably the closest you'll get to that middle ground of an established manager that is not elite but has won trophies and punched above his weight recently (iirc he won more points in his first year or so at Villa than everyone except Pep and Arteta, he took Villa from 15th iirc to Europe last season etc). That's not say I think Liverpool should appoint him but it's worth noting that he's outperformed the media darling RDZ by some distance despite the latter inheriting a team that were in the top4 when Potter left compared to a team just above the relegation zone when Gerrard left.