Girona will not be "that" good again, not for a while I assume, it's clear that they had one good year. Just because they are part of City group, doesn't make them suddenly that much better, they had a good year and they liked that, but they are going to end up realizing they are not a big enough club to consistently do this.
As I've said before, a mediocre team like Girona ability to finish a season as flawlessly as they did a few seasons ago is simply a matter of luck. I've always said that teams like Girona and other mediocre teams struggle to maintain consistent performance. Therefore, we'll never see Girona achieve the same results again, and even competing for a top-5 finish is highly unlikely.