Chill on the alarmism for a second and look at what they are actually ruling on:
Whether the following provisions, D.C. Code §§ 7-2502.02(a)(4), 22-4504(a), and 7-2507.02, violate the Second Amendment rights of individuals who are not affiliated with any state-regulated militia, but who wish to keep handguns and other firearms for private use in their homes?
They have limited their scope very narrowly, I can only guess that this is an attempt to keep out of the situation as much as possible.
They are ruling on whether or not:
1.) the RKBA is an individual right.
2.) this right applies to individuals
3.) "firearms" applies to handguns as well as long arms.
4.)
this right applies for private use in your home
While case history will dictate this decision goes in favor of the gun owner's, that last element (#4) ensures an easy cop out for the SCOTUS. They can rule in favor of gun owners on all points of the order and
still not impact current firearms laws that do not ban private ownership in your home. Which is to say, they can overturn the D.C. gun laws, but no others that don't restrict the ability of a person to own a firearm, but never carry it or use it.
I'm kind of ashamed of our SCOTUS for passing the buck on this one. However, I think this decision will change very little. They are going to rule that the RKBA is an individual one that applies to all individuals and includes handguns. They they are going to rule that this right only applies in the privacy of your home.