Look at Arsenal, they thought they were on their way to the EPL title last season, but in the most important part of the season, City showed them why they have more experience to handle the pressure of the last few weeks of the season. Right now City are just unstoppable in the Premier League and i can't see any team usurping them.
Manchester United will definitely be stronger if Harry Kane is in the team. But becoming more experienced is important to win the title. Over the last few seasons, we have seen the dominance of Manchester City in the Premier League. And with each season, the City continues to increase their strength. And so it is very unlikely that Manchester United will be too strong and win the title next season.
Last season we saw Arsenal's performance. They lost the last few weeks of the season due to a lack of consistency in performance. If you want to win the title, you have to play consistently well. And besides the main squad, there should be talented players on the bench. Otherwise, it is difficult to maintain consistency of performance.