Funny, I saw Traveller as more akin to the a mixture of the Soviet and Imperial Russian models:
best and brightest boots immediadely become NCO trainees, rest serve a term, and hope, if they stay in, that they eventually make NCO grades. The best and brightest 1st term NCOs' become Praporshiks (roughly, Warrant grades, but functionally SrNCO's and platoon LT's). Officers come from two areas: acadamies and the best NCO's overall...
Then again, let us not forget, Russia had a meritocratic structure of ranks by 1600, jointly structured civil and military, which included patents of nobility to the senior grades....
Sounds dangerously like Traveller.