As an inexperienced former MM it would seem to me that the Navy's money concerns would be better served by replacing the non-flying jobs with LDOs and CWOs.
Take disassociated tours for example: It would seem to me that a tour as a shooter for a P-3 NFO is pretty useless and disheartening except to gain some 'breadth' and 'real' sea time (and of course for the DH board as the system is now) but doesn't make him/her a better TACCO, etc. A smart and hard-charging AB1, on the other hand, would probably kill for the chance to fill such a tour. Additionally, I believe having these mustang programs pay for themselves through their effects on retention.
Then squadron tours could be lengthened to compensate for the elimination of the disassociated sea tour, e.g. 4 yrs JO, 3 yrs DH, providing for more spread of ground/collateral jobs and time to breakout or a smaller overall number of flyers.
Well, thats what I would try having no real f***ing clue what I'm talking about.
FYI, the age requirements for STA-21 and I believe most other commissioning sources are 27 waiverable on a month-to-month basis for prior enlisted service up to 29 for pilot and 31 for NFO.