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.
Arsenal is actually on a balance when it comes to squad. It won’t be bad if they want to add extra players to their squad but even with the current squad, they are very much solid to compete with top clubs. The problem I see with them is their relenting attitude when they’re suppose to put more pressure. They normally start very well with good energy but perhaps, the English media hype is one thing that deceive them thinking they have achieved much and begin to slow down their performance and end up losing important points.
Talking about Arsenal's balance as a team and if there's any need to overhaul the team, I personally do not think they need to overhaul the team because the club manager Mikel Arteta have been building the team for over four years now. The young Spanish manager have been able to significantly improve the Arsenal team than we've ever seen them since the club's legendary former manager Arsene Wenger left the club so I think they only need to make few significant additions to further strengthen the team and make them more formidable than they were last season. Gabriel Jesus used to the club's first choice striker but last season, he struggled to perform well after suffering injuries which made Kai Havertz overtake every other striker in the team to lead the attack. So if there's any position Arsenal really needs to strengthen, I think it's the top 9 strikers position.