I cannot comment as an expert, being a non-military observer; that aside my reading of a history article recently on the WW1 US Army illustrated the pain it underwent in France / Belgium. In WW1 it took a long time, at horrendous cost, for the British & Commenwealth armies in France to reach combat superiority - in which training was one factor.

In my reading on WW2 the training pre-1939 and into the war of the German Army NCO and junior officers is highly rated (see Peter White's 'With The Jocks').

Post-1945 history has plenty of examples IMHO where expatriate officered armies, or ex-colonial armies have failed or regressed to a mob, e.g. Nigerian Army when the Biafra War started.

I don't know what the mixture is for success, although I'd hazard a list: fit commanders, able staff officers, excellent battalion level officers and NCOs. Resting on a base of willing and disciplined soldiers - who mindful of Ken & Tom - who are paid, supplied and cared for.

Now back to my armchair or "bunker".

davidbfpo