Since the soldiers' place of duty is often either in, or involves frequently entering these federal buildings, and DoD civilians place of duty is almost exclusively in said buildings, this would look good on paper but you would find yourself in a situation where no one could carry in the workplace where an active shooter scenario might occur. If Trump passes such a law it would be great, but make sure to lift these restrictions so that only exceptional locations (federal courthouse) are exempt to carry.
The other problem, for bases in NJ, MD, DC, etc. is saying you can carry on base is one thing, but if you cannot legally carry in the state in which the base is located it buys you nothing. So if I have a PA carry permit, but have to travel to Fort Meade, Fort Detrick, or APG I'm still screwed. Having this PLUS national Constitutional Carry would solve this problem.
It was this insanity that allowed Fort Hood massacres one and two to occur.
I suspect the military would have to have a policy of every one above E5 will carry on duty, as well as every officer.