Joao Mario and Coco must be the 2 worst transfers we have made in our history. Can't say anything about Gabrigol yet, I'm afraid that it might turn out like Coutinho after some years.
Personally, I don't think so.
Coutinho at least had some games at Inter and showed a few things, plus the coaches did think he was talented. He also went on loan to Espanyol and did well.
But with Gabigol, it seems 3/4 coaches didn't even care enough to give him chances. Not to mention, that when he went to another team, the exact same thing happened and the Benfica coach obviously doesn't care to give him any time.