The only thing that might be possible given the limitations would be to bring the Infantry Revolution early. In most places, fighting men were trained from early boyhood to use weapons, so revolts by the peasants was pretty dangerous (an untrained and unarmoured man with an agricultural tool in his hands can be dangerous, but against trained troops protected by even a small amount of armour, they are generally disadvantaged).
The Infantry Revolution was triggered by the appearance of weapons and tactics that could be used by large numbers of relatively poorly trained troops that gave them the advantage over armoured nobility. In Europe this was the introduction of the crossbow (the English Longbow and the Ottoman compound bows required a lifetime of training, while a crossbow could be used fairly effectively after about a day's training), pikes in dense squares and various specialized pole arms which allowed a man to go one on one with a mounted knight and pull him from his horse, skewer him or crack open the armour with the extra leverage (the halberd head allows the user to do all of the above).
Of course a rabble armed with these weapons would still be scattered like chaff; the other part of the revolution was to convince people to stay in close ranks (a pike square with a frontage of 10 and a depth of 10 can rapidly manoeuvre around a battlefield) and cooperate (having rows of crossbowmen between the pike squares gives long range protection, while the squares hold off cavalry charges and even oncoming infantry. Groups of halberd armed men between the squares or in reserve can trade off with the crossbows when needed for the close fight, while the crossbowmen fall behind the pikes).
How our hero could convince people to do this would be an interesting trick (perhaps the core of the story). I suspect the crossbow would be an easy "sell", since even merchants can see the benefit of being able to effectively arm everyone in the wagon train or merchant ship, and poor nobles can effectively defend their castles by arming the cooks and scullery maids in an emergency. Getting people to work in close ranks takes more time and energy, and was generally picked up by the people of walled cities as a means of preserving their freedoms against the nobility, but this implies a level of social organization which might not be there yet.