The baby will be cut in half. Nothing will change.
After listening to the rhetoric presented by the interested parties, and their various friends briefs, I believe the supreme court will apply a template similar to that expressed in the DUI checkpoint decision, which, if you remember, gutted the fourth amendment.
Namely, that the .gov has a "compelling safety interest" in preventing gun deaths, that trumps the constitutional RKBA.
In other words, much flowery verbage will be offered up in support of the individual intent of the 2nd amendment, but it will end up being worth about as much as a bucket of warm spit. So, obsessing about the split on this question is missing the point, eh?
The "compelling safety interest" will end up justifying every gun control measure now in place, and every wet dream Sarah Brady and Josh Sugarmann can manage to bring before the new receptive dem. administration.
Round about June, when the decision is released, it will just be another Rorschach test, reflecting everyone's predispositions on government and authority in general. Those who normally genuflect to "the rule of law" will hail it as some incarnation of genius, preserving the intent of the constitution, while at the same time rendering it practically meaningless.
They will expound on the nuanced application in states, cities, and districts, as we are reduced to owning only trigger-locked pellet guns in our homes.
Among freedom loving citizens, to quote Lawrence Thayer:
"...there is no joy in Mudville - mighty Casey has struck out."