someone has already did that -->
http://forums.taleworlds.com/index.php?topic=216424.0FEATURES:
-The player will get a value in fatigue based on their heatlh points and modified for agility skill.
-New stamina bar between health bar and horse bar.
-Now the player gets tired if he runs, dodges, jumps ...
-The fatigue is a graduate of the weight carried by the player above (for example, a Saxon warrior equipped with chain mail, shield, sword and helmet will tire faster than a nude Pictish raider)
-Each hit or block tires according to the weight of the weapon.
-The player will hear himself breathing when he's very tired, and will suffer exhaustion as his stamina bar reaches 0, being easy victim to his rivals.
-Saving stamina, decide when to hit or defend, when to charge or waiting for the enemy to save energy ... will be significant.
-The light troops take on new importance as a support to the heavy infantry, or even as a force of harassment.
-In our tests we found that the strategic possibilities multiply.
seems good to me , the problem could be the balance .