Being a soldier and being an officer are two very different trades, and they don't require the same skills. An office doesn't need to "wield", he only needs experience as an officer. That doesn't mean that officers shouldn't know how to fight, but it's not required, and a general who fights is often endangering his army more often than not.
It was in the Revolutionary Wars when, precisely, this was more apparent. Suddenly anyone could enter the officer corps, and thousands of commoners with skills in leadership, not blue blood or lineage, became some of the best army commanders ever seen until that point. The sheer amount of excellence inside of Napoleon's tent, the brilliance of most of his Marshals, of whom more than half were sons of tradesmen, peasants and artisans instead of nobles, is astonishing.
That said, I don't look forward to a Napoleonic DLC. I'm not in love with that style of combat, even if I'm very much interested in the period.