You learn on the job, that's why Pep stuck rigidly to the system in his first season despite the "he's fucking shit", "he can't do it in England with his fancy bollocks passing", "he needs to be more defensive because he's been found out" comments from our own fans, nevermind the cünts in the press.It's not really changing to a Pivot to accommodate Rodri, it's changing to a pivot so we become less threatened by counters like we've been this season. It may be because we've had Laporte out for the whole season, but Rodri not having the legs and tackling ability of Fernandinho also plays a huge part. So playing him in a pivot until he's fully accustomed to the PL is a good solution in my opinion
We got made to look stupid at Leicester, Everton and a few other places when they exploited our weaknesses (e.g. Zaba's lack of pace) but it was the only way to make sure the likes of De Bruyne, Fernandinho, Silva, Sterling and Aguero all knew what was expected the next season. Changing to a double pivot to accommodate Rodri is pointless, it helps results short term but fucks us up again for next season, as Rodri won't have had chance to work on just being a better single pivot.