the reason people think he should tank Miami is 'cuz he won IW & wants to win Paris. And don't forget 'cuz after winning IW & Miami b2b last yr. he wiped out his feet w/serious plantar fasciitis. In fact, IW was the best I've seen him move since Houston in '04.
Further, even if we take a wildly optimistic best-case scenario & say he wins Miami & Paris, the pressure would be exhausting, and almost certainly adversely affect him @Wimby. Better to go back to Europe, stop home & rest for a few days, be under no direct mental pressure for a few extra weeks, hire a clay court practice partner perhaps (Tony can't run anymore tho I heard his strokes are still exc.) & get extra time in practicing on clay. (I even thght. it would make sense for him to go down to Latin America this winter & play a few of those. Sure they may have easy draws, but I think his chances for winning Paris increase if he spends Feb-June on clay, w/only a quick break for IW. Then he's thinking of clay, exclusively.)
Also, read Mats bit from Inside Tennis recently in which he said Roger needs to practice on the stuff for at least a month first. If he takes Miami seriously, he's going to be sufficiently tired when he gets to Europe, that by the time he's rested he won't have a month of good preparation.
But, those of you w/the poinnts argument are persuasive. It just significantly dents his chances @Paris, imho.