I don't disagree that Matip reads the game better, but he's truly an injury prone player so I'd go with his sale if we get an offer. Gomez reads the game quite well IMO (at least as well as Nat Baresi) and has only just turned 24. You don't sell international level CBS just coming in to their prime after spending 7/8 years developing them. Young CBs get injured, it's common as all hell. If he's still having issues at 27 then you sell him.
You do know that he as had two Ankle surgery's already and the latest is a Petella injury problems
It does not bode well for us (Liverpool) or Gomez. I can see him missing plenty more games