I'm talking more about them cutting our military back to the days of WW2 and replacing humans with technology. Good/bad idea? Consequences etc
Cutting back the Defense Department to the size that the Navy and War Departments were in 1945 would actually require a radical expansion of both forces. Consider that at the end of World War II, we had almost 100 Army divisions (infantry, armored and airborne, plus all the men in the Army Service Forces), the same number of wings in the Army Air Force - fighters, bombers and transports - and a thousand ships in the Navy ranging from battleships and fleet carriers down to destroyer escorts, PT boats and all manner of auxiliaries (tankers, transports, landing ships, bouy tenders, etc.) and all of this tied up most of our economy and manpower from 1940-1946. We have been upgrading the technology all along - the nuclear carriers we have today can cruise longer and deliver more destruction than the entire Seventh Fleet in Vietnam, to say nothing of World War II, and that's without taking tactical nuclear weapons into account. The same is true for the Army and Marines: we have the M-1 Abrams instead of the M-4 Sherman, the burst-firing M-4 instead of the single-shot M-1 Garand, and every grunt wears body armor, which was unheard of in WW2.
In the end, though, as our politicians keep having to relearn every decade or two, there is no substitute for a heavily armed, well-trained teenager dug in on the ground you want to hold - or attacking the ground you want to take. See the opening chapters of T.R. Fehrenbach's This Kind of War, which are all about the post-WW2 demobilization and its consequences when the Korean War broke out.
On the civilian side, you could definitely accomplish a lot by streamlining the bureaucracy and improving its information technology infrastructure, but all such reforms tend to get tripped up by well-intended civil service regulations that make it nearly impossible to fire anyone and purchasing regulations so onerous in their complexity that only a handful of Beltway Bandits can or want to deal with them. A good start would be to pare back Washington to its original core constitutional functions, but every time that's suggested we get the speeches about feeding dog food to poor kids and throwing Grandma in the snowbank. >_