In Dalglish's system, Meireles plays a role that's filled scarcely less competently by Maxi. A generic midfield runner who can be shifted around the team as and where there are gaps. Noone will pay anything for Maxi, while they will for Meireles, plus Maxi generally has a better scoring record than Meireles, whose 5 goals last season was better than his average at Porto, but which were all scored in a single spree. Going by evidence, it's reasonable to expect Maxi to contribute at least as much as Meireles in Dalglish's system.
Now if you claim that he's best as a deep lying playmaker I think the above helps explain why under Kenny we could afford to let him go when we have other deep lying central midfielders in the squad.