I think skipping Miami makes sense. The last hard court tournament before the clay court season adds no value. Skipping both MIA and MC gives him time to prep for the FO & Wimby stretch.
But I also see political reasons why he might be skipping Miami. Miami is run by IMG and having broken up with them, I think there is no love lost. Also, its Miami that put the kaibosh on the prize money increase that IW owner Ellison was willing to give to the earlier rounds. Heard that Roger was pretty upset with that decision esp given ATP Chairmain Brad Drewitt notedly abstained from voting thus giving Miami the chance to squash the offer.