First, Obama doesn't have a universal health plan. He suggests some expansions here and there, and a restructuring of the policies health insurers can offer, but there have been no particulars published.
It's difficult to know what impact his proposals would have, except that there will be adjustments. Doctors tend not to be stupid, and they generally figure out a way to come out OK, with alterations in practice, going where the money is. The great bulk of his plan is copied from what Romney did in MA, so you can look there for some hints, but until we get into the particulars, there's really not much of a way to judge.