I think Arsenal doesn't have to make a major overhaul to become champions because they already have a pretty solid squad and a good coach. At most, they only need to sign a few players who are really needed and don't have to make changes on a large scale. Arsenal's real problem is that they still don't have the winning mentality that Man City and Real Madrid currently have, and I think if on several occasions they can reach the final, it will form that necessary mentality on its own.
Real Madrid and Manchester City continue to lured their strength towards major titles. You're saying Arsenal will win the UEFA Champions League title? Funny how it sounds because the Gunners are completely categorized as a struggling club because they've failed to win major titles over the years. With the epic consistent performance, they still can't possess the full domination of the English Premier League because of just one man and his incredible club. Pep Guardiola have been a major barrier for Mikel Arteta.