Considering the 'style' he tried to impose on the team it's clear that the year coming 2nd wasn't much of anything to do with Rodgers. If you have Suarez, Sterling and Sturridge on the pitch you might say for instance, lets play possession but if you have the chance to break by all means.... then those three break forward at crazy speed every 8 seconds. They played a style Rodgers doesn't teach, doesn't intend and hasn't remotely come close to with other players in the side.
As for his success at Swansea, Martinez took over a league one side iirc, became champions, brought players on a shoe string budget, built a team that came was it 7th in the championship before he moved on to Wigan. Rodgers took over a prebuilt team and took the next step, then got 11th in the prem league with largely Martinez's team and style. When Rodgers left Swansea both managers after him did better. I regard that much like Mourinho winning the first title with Chelsea though he did change their style over time it would have taken a genuine retard to not win at least one league title after Ranieri left, Ranieri would 100% of won the title that next year had he stayed.
Without Suarez there isn't a chance Rodgers would have come 2nd or played the style of football that 'happened' that year, imho. Personally I see a manager as successful if he improves the team he has. Any team can have a freak finish when you get very few injuries, a couple of insane years for players and a lot of luck. The team he has left, I can't think of any players he's improved obviously, only regression of multiple players.
He has final say on buys, people make a huge deal about a transfer committee while ignoring that EVERY other team in the world has a group of scouts who find players for managers to have a look at. It's how football runs but not called a committee people don't freak out about it. Likewise how many top teams give little to no say to the manager? Barca, Real, Bayern.
That he didn't win any of the other cups as well, it's entirely NOT unrealistic to get into another cup final or win one. ARsenal came VERY close to losing to Hull, then thrashed Stoke. Is it really unreasonable expectations to expect Liverpool to be capable of winning one of the cups considering who got into the finals? With the top teams having not cared about the Carling cup for years and the FA cup is falling to the wayside now, Liverpool being just outside the top four should have had both cups as a very realistic target.