You are so valid, current performance is not indicative of future performance, Man City did well this season but that doesn't mean that they did not have changes. And if Arsenal could have done better than relenting when they needed to fight most, they would have won the title. Next season is another chapter that no one knows yet, there are viable contenders in the line-up.
A good contender to be watched for is Liverpool, I will not underestimate them with the comeback they displayed in the last months of this season.
I think Man City remain favourites. Perhaps what will surprise is Newcastle United. Others as usual, Arsenal, Man United, Tottenham, and Liverpool, may also later Chelsea. I don't have any specific predictions, but I favour Man City for the current conditions. I believe this season's transfer market is very influential for next season's competition. So predicting one club that dominates is very difficult. In addition, we know, EPL always gives surprises that are difficult to predict.