Yes, under Adkins in 2012/2013 he showed glimpses of real class. I remember that Villa game (3-1 I think) and he bossed it - he almost looked Zidane-esque. When he came on last year you could see he wasn't naturally suited to Pochettino's pressing game and seemed to be running about like a headless chicken at times. I think if we play Gaston we have to accept certain limitations and allow him to do his thing creatively. Like I said before that killer ball is absolutely priceless.
Coonfidence playes such a huge part as well - prime example of that is J-Rod who didn't really seem to come into his own until he figured out he had the backing of everyone. I suspect Gaston (and to a degree Yoshida) would be transformed by being given a regular starting berth.
On the confidence point, Pelle's performance last night showed as much he seemed to grow an extra foot when we chanted his name. He has to show that in the prem, but last night tells me at least he isnt championship standard.