I think its good to rank clubs not just in terms of most recent form but also, wealth and attractiveness on the market and potenial.
I think Barca, Madrid and Bayern are on their own. They are guaranteed titles, wealth and are very attractive on the market for any player. They naturally collect all the best talents in the world.
On the second Level, is Juve, Chelsea, and PSG. What the latter two lack in history they make up in wealth. They are also favorites in their leagues.
On the third level is City and probably United. Super wealth and one title is a great season. Utd will ofcoarse try to join Bayern, Barca and Madrid.
Fourth level is Arsenal and ATM though the latter peform at a much higher level than Arsenal and are all about character. Unlike Arsenal.