Correct me if I'm wrong but didn't Columbia v. Heller hold that the Second Amendment protects a person's individual right to possess a firearm unconnected with service in a militia?
I think your argument that training requirements are consistent with the original intent of the Second Amendment is wrong. From my cursory reading of the Militia Act it looks like it was enacted out of necessity because we lacked a real military.
I'm not sure the Founding Fathers intended for us to have a military that would displace the responsibility of the people to defend themselves.I believe the function of the Army was to provide organizational and logistical support to a force of the people (militias). I think they'd be rolling in their graves to find we built a military that could wipe out the people and handed the reigns over to the Government. And it doesn't matter too much whether it's Obama, or Trump, or whoever sitting in the big chair in that regard.