Rafa pros:
Tactically excellent
Loves LFC
Won trophies when he had support from the club owners
Set a significant number of club achievements (including points totals, winning streaks, goal scoring records, clean sheets), turned Gerrard, Torres, Alonso, Reina, Mascherano, and Carragher into world class players,
Made CL qualification our right rather than our privilege
Made us the best English team in European competition
Railed against a regime that supports Fergie (apparently a lot of people on here think he should not have done that, generally the same people on here who think such action by the club now is acceptable)
Revealed that the club was being conned by the owners (but many people on here still refuse to back down on the hanging of dirty laundry in public issue, people who would obviously prefer H&G were still milking the LFC cash cow - and we accuse the FA of double standards)
Rafa cons:
Not a man-manager (as though man-management is the ONLY way to succeed)
Arrogant and unwilling to admit his faults (name a top manager who is not)
Bought poorly in the transfer market when he had no support from the owners (never mind that sell-to-buy is not a transfer strategy that will give you regular CL qualification - ask David Moyes)
Demanded that the owners match his ambition (apparently this is a character flaw, but name a top manager who does not - Shankly himself abandoned/was fired by other club owners for the same reason)
So essentially Rafa had all the flaws of a top, non-man-manager, but backed it with success and the establishment of a significant number of club achievements in only 6 seasons. One can only wonder what he could have achieved had it not been necessary for him clash with the owners. (People mention Milan, a club abandoned by Mourinho because it was clear the oldest squad in Europe could no longer succeed [cf Chelsea last season and this if you don't understand this point], and with a club owner who promised a large transfer fund, waited until Rafa sold key players, and then gave him no money - and yet he still won 2 minor trophies in six months - I'm not saying Rafa didn't have a hand in this, but I think most people understand that club management and the first team manager have to see eye-to-eye in order to succeed).
It's still not his time to manage LFC as there could be lingering bad blood between him and senior members of the squad. But I wouldn't dismiss his chances of returning once Gerrard retires, unless someone has led us to the EPL title and kept us in the hunt season after season.