Having that new manager come in in March seems to have benefited a lot with more regular game time. Watched back his performances against Atletico Madrid and Bilbao and he was very good, got a very good assist in each.
Imo, and this might be a controversial statement that could turn out to be completely false, I think he has the potential to push into the world class bracket ala Salah or KDB. His technical fundamentals are so good, he's one of those players whose bodies are just in tune with the ball when he runs, and he can play some great passes too.
What he's been severely lacking in is game time. Since he broke through for us under Moyes, he's had two terrible years under Van Gaal (including a completely pointless loan to Dortmund), and a loan last season to a beyond rubbish Sunderland team that's now finished bottom of the Championship this season with a lot of the same players. Another 2-3 seasons at Sociedad where he starts week in, week out as one of the main men where he'll be able to grow his game will do him the world of good. By that time he'll still only be 25. I like that he's showing more aggression in his recent matches, he has a lot of talent and if he can get the fight to grow he could become something special.