I spent 15 years in the ranks before I CFRed, making it to Sgt. I was 33 years old when I did it, so I still have a lot of legs left in my "second career."
I think like anything, it depends on the individual versus the collective. I met a lot of very switched on DEOs and ROTPs that had needed a little coaching, but were strong leaders, planners, and thinkers in their trade. I have also met quite a few CFRs that at literally in it for "Freedom Best 5" because they plateaued at MWO.
IMHO, forcing an Officer to serve first as an NCM is folly. No guarantee that there will be any experience or knowledge gained from the exerciae that couldn't be gained with a strong mentorship from a competent WO/SNCO.
What does need to be instilled in any leadership entry (DEO,ROTP, UTPNCM, CFRP) is the concept of servant-leadership; you're in command, and your troops will move heaven and earth to get your plan off the ground. Your job is to move heaven and earth to ensure they are well trained, well equipped, well disciplined, and well led. That is lacking in a lot of my sibling officers of every origin and rank level.
And in reference to CFR, I would only have Sgt/WOs eligible, with at least a minimum of 15 years left before CRA. Anything else can be a SRCP scenario.