Interesting question, but answers given seem to suggest memory loss. It is very unfair to give full credit to Suarez for that season - as I remember it - we were winning with clean sheets at the start of that season without him because of a ban. So my analysis is the follwoing:-
1) Under Rodgers we had players who came good that season with great form, in the three S's (Sterling, Studge, Suarez). Also Hendo started to emerge proper that season, and SG was delivering what remained of his last spark, with Coutinho playing his part now and then.
2) What Suarez did do for us was the 'pressing' - all by himself, and with Rodgers teams - there was no clear build up - it was all about getting the ball to the front men to do their 'magic' which they did against nearly all the teams.
3) It goes without saying that if Klopp had Suarez - he would be playing 4-4-2 as as Suarez alone could do the pressing by himself and the scoring.
4) Under Klopp the team mentality is far higher up the order; the build up play is more organised; there is a defensive measure in place and players look more disciplined. We would for instance against Crystal Palace folded today under Rodgers. Under Rodgers we really needed that X number of goals cushion to be sure of victory. This season we have managed to defend a one goal lead under pressure against Chelsea, Swansea, and WBA.
This is a much better 'Team' - it offers the opposition few chances; and is fitter than any of our competitors. I honestly think that when opposition teams press us - I just know they will not last for more than 10 minutes (unless its Spurs) before they have to withdraw - our levels are well high now. I really likes Klopp's approach to defense - which is basically NOT to give the opportunities to the opposition to create/ have corners etc.. that kind of works.
In truth - this team gives me more re-assurance of success; than Rodgers team because with Rodgers we rightly/wrongly associate Suarez as being the main gear box for that team. The current Klopp team is just awesome to watch because of the 'whole' approach - Rodgers team was great to watch but only because Suarez made it happen.