DCOIC is pretty easy. The toughest part is getting little sleep. You'll also drop a couple of pounds while you are there. I went in the Fall before the Winter set in and lost 15 lbs due to the constant exercise and walking everywhere, and only eating three meals a day in the galley/mess hall. At least when I went, we were not allowed to eat anything with sugar in the mess hall.
I would really prefer that all DCO candidates attend
Officer Development School (ODS), which is the active duty equivalent. Off the street civilians with no military background would benefit greatly from the full ODS course. IMHO, sending people like this to a two week DCO course is not setting them up for success as an officer.
I would say that DCO is sufficient for prior Enlisted or current drilling Reservists.
I like the Marine Corps way of doing business. Every single officer, Active or Reserve, regardless of commissioning source attends
The Basic School (TBS). This is the best way of doing things as everyone receives the same baseline level of training.