Alonso leaving arguably had the bigger impact in terms of the overall team. They were in a similar position in his last season to that in Suarez's last season - 2nd in the league. But they had a stronger overall squad including a fit Torres, Gerrard, Mascherano and Reina, yet still dropped to 7th in the league the year after he left. That was a definite under performance based on the quality of the players they had at the time imo, and they still haven't replaced Alonso with any decent playmaker despite trying Aquilani, Allen, Coutinho, Adam etc. This season, they have fallen away in a similar style, but only to a level you'd expect. They have a worse squad than Utd, City, Arsenal and Chelsea, and worse defence and attack when compared to Southampton and West Ham, so you'd expect them to be about where they are now. Suarez was definitely a big reason for their rise to 2nd last season, but now he's gone they are just back to where they were before he arrived. But before Alonso arrived they were a top four club, since he left they have been top 7.
Suarez was more important IMO, not only did he score goals but he set them up and didn't always rely on anyone but himself to get us in front. Special player
Alonso was more important. You were a far better side with alonso than with suarez. Who is frankly proving how good he really isnt. Has he even scored for barcelona yet? In a league where scoring is easier than on a brothel...
Both Alonso and Suarez were important for us but at this point I would say we need a Suarez more than an Alonso.
Alonso is brilliant but players like him need other good players around them... he can't run so needs someone beside him, he needs movement in front of him, needs a team which dominates possession... then his skills (which are numerous) are given full effect. Liverpool might as well have been Gerrard & Friends for periods of his career.