Ha, Ronaldo leaving will make Madrid more formidable in the long run. Ronaldo was shit(for his standards) for more than half a season and yet Madrid still won La Liga. Imagine Messi playing the same for us for half a season? We'd be fighting Sevilla for 4th place. They still have a great team. That midfield is going nowhere. Those 2 fullbacks are going nowhere. Chances are going to be created with Ronaldo in the team or not. Someone is going to bang them in. Consider his overall efficiency is not that great for a striker and even a small improvement in goals/shot scored is going to keep them at the same level.
Considering the fee they will get for him and investing in the next batch of superstars(Mbappe, Donnaruma etc.), and whoever rises up next, they are going to be ever more dangerous. Asensio looks a star in the making too.
For Barcelona it's better that he stays. He's going to decline more and more over the next years.