His performance proves if he was not the problem, and i saw similarity between him and Anthony while at Betis. The only problem is he has only a long season loan, and Everton must perpare at least £50m to get him permanently.
While I'm happy for him, I think it's too soon to say anything about his long-term form. There have been many cases where players who go out on loan perform decently in the first few games but then fade away for one reason or another. I remember Lingard or Coutinho at Villa. Still think Grealish will perform decently though, just that it's too soon to say anything for me. 50 million pounds isn't that horrible on the current market, especially if he can rediscover or improve his form.
You're just taking the example of player who was inconsistent, but there is also player who being very consistent when he gets loaned to the another club. Just take a look at Anthony. The ratio will always be 50:50 for the success or not. However, as long as grealish will not be injured. I guess he will always able to perform like this.
Only hope moyes will able to maintain his game time to ensure he's fine until the end of season. his glass knee is the thing that is always worrying me hehe.