Hmmm..that's very debatable. I'm not happy with Merts performances either but I really don't think bringing Gabriel in will improve us that much...if at all. Gabriel or Kos are not perfect, Gabriel especially is quite naïve in his positional play, he obviously makes up for that with his speed which Merts doesn't have.
Gabriel's distribution is even worse than Merts, it's one area he really needs to improve.
The defence are accountable for conceding goals but without the protection from Midfield they are like lambs to a slaughter. I stand by my opinion that if we had Caz and Coq in midfield or a more disciplined structure to our midfield I.E. not Ramsey & Flamini we would see an improvement in our defensive play.