You can design just about anything, but your only consumer would be some 3rd world country that needs to fend off it's guerrillas.. and uprisings.
Now a days you just need a drone strike, and a satellite to track enemy movement. You can literally have a guy in a cubicle sitting 9 to 5 behind a desk shooting people across the hemisphere piloting a drone, and the training required.. a high school diploma.
But if you're curious in what's going on in the field of armor advancement.. testing. Check out a military simulator called Operation Overmatch.
If I play my cards right