It can be done either way. You can have a pure defensive player sitting back with two players in front of him doing more of the playmaking duties, or a deep-lying playmaker sitting back and a workhorse next to him providing the legs.
Personally I do prefer the latter, but more importantly it does suit our current players better. We'd only need to buy the one player, as we already have Herrera who is well suited to the workhorse role. It's also the same set-up that Pogba had at Juventus. The other way we'd probably have to buy two players now, as Pereira likely isn't going to make it and Gomes isn't ready yet.
Of course, the ideal would probably be having all three of them being fairly good at controlling the team around (similar to how Pep normally sets up).
Fair enough. But let’s not forget the set-up we’re currently employing has provided a +11 goals difference in the last 4 games and is currently working perfectly for everyone involved, especially Pogba who’s been directly involved in half of the goals scored. Rice would pose as a pretty straight forward replacement for Matic.