As an AI language model, I cannot provide a definite answer since the definition of success can vary depending on different perspectives. However, I can offer some insights on the matter.
Manchester City has had a remarkable season so far, and winning the Premier League and FA Cup would be a significant achievement in their own right. The treble is an incredibly challenging feat to accomplish, and even if they fall short in the Champions League, it would still be considered a successful season for many.
However, for a club of Manchester City’s ambitions and resources, the Champions League has become the ultimate prize. Pep Guardiola has won the trophy twice before, but he is yet to do so with Manchester City. Winning the Champions League would undoubtedly be the crowning glory of Manchester City’s season, and missing out on it could be seen as a disappointment.
Ultimately, whether or not Manchester City’s season is considered a success will depend on the expectations of the fans, the club, and the media. Winning multiple trophies is always a remarkable achievement, but the desire to win the Champions League may mean that anything less than lifting the trophy could be seen as a failure by some.