Peasants with 3 gold chevrons in rtw could take on some serious units due to their increased morale/stats/ and large unit size.
Is this not as it should be. Just because the son of some noble can afford some shiny tin plate and a big sword does not mean he should rule the battlefield. A humble peasant that has fought many campaigns would likely gain skills and experience that is worth far more in the heat of battle than a bigger sword. It would teach you when to fight and when to leg it if nothing else.

The only problem I found with experience in RTW is that cavalry, especially Generals gained experience too quickly.