General and Flag Officers include Admirals. I found an article written by a Colonel in the Marine Corps Reserves, which supports your estimate of the current level of these officers in the DoD. But, the number of these officers during WWII were substantially more than your number. Read on:
Are There Too Many General Officers for Today’s Military?
By Gregory C. McCarthy Joint Force Quarterly
"There are approximately 900 Active-duty general/flag officers (GO/FOs) today of 1.3 million troops. This is a ratio of 1 GO/FO for every 1,400 troops. During World War II, an admittedly different era, there were more than 2,000 GO/FOs for a little more than 12 million Active troops."
During WWII we had two and a half GO/FOs supervising ten times the number of active duty troops than we have today. The number 17 is wrong, It may be easier to track the number of GO/FOs today, since that number is limited by law.
Today's weapons systems and other functions are far more high-tech requiring a more skilled and highly trained work force. A person supervising a company, approx. 250 people, of computer geeks responsible for Nuclear Warfare Systems would outrank an Infantry Officer in charge of 250-grunts.
To answer your question, I don't think we need more GO/FOs. My original posting never broached the subject.