I think the rotation was warranted, although I suspect that Son will be back in against Arsenal. The thing that Conte talked about this week was how, in a two-man midfield, both midfielders have to be "good with the ball and without the ball." His answer was in response to a question about why Bissouma wasn't playing but it's not as if Hojbjerg and Bentancur have been amazing this season either. Conte eventually had to put Bissouma in and play with a midfield three because Leicester had control of play. I don't see why we shouldn't start the game against Arsenal with a 5-3-2/3-5-2 as we're likely to get destroyed playing 3-4-3.