Real Madrid had their way, FBs doing overlaps in wide areas, lots of crossing, Benzema's support role and so on. Ronaldo was a crucial aspect of the system. Now he's gone, they didn't have to change the system dramatically, but became much less effective (they can, of course, but it's not necessary like it will be for us) . Barca, on the other hand, is a team build around Messi (and Suarez to a lesser extent), a setup which aims to give them freedom. That's one reason why it's pointless to speculate about post-Messi Barca based on what we've got now. The other one: our core players will all leave by the time Messi hangs his boots. Rakitic, Pique, Busquets, Suarez, now Vidal... unlike Madrid, we'll have to build a completely new approach. Because replacing Messi 1 on 1 is impossible, and not just quality wise. Messi's role takes many sacrifices which no other player in the world can make up for. It's better to look at how Barca coped during Messi's absence. Better shape, clearer roles, more usual team that what we've got now.