If you watched any of the bannerlord devblogs, you would notice that they too have added sprinting. Can you sprint in real life? I'm sure you could if someone was trying to kill you.
For stamina- maybe stamina could only be drained by bad blocks, sprinting, and heavy attacks, so that players can use normal attacks without too much penalty. Also since it's a RPGish game, will you be able to increase a characters stamina?
If Bannerlord has sprinting, that's its problem.
A medical specialist recently told me that nobody understands what really causes exhaustion irl. It can't be measured and is pretty much a complete mystery. A doctor can not tell if a person feels tired. It seems like tiredness can be sort of crudely bypassed with adrenaline etc, but even those parts of the system that are somewhat understood work very organically and can't be properly simulated by people who actually know what they're doing. For that reason, when a character breaks down from "low stamina" in-game, the player can't relate to it, because the player would not behave in a remotely similar way in the same situation. Now, the player would also not behave in the same way as someone with endless energy and vigour, but that difference is quiet whereas being affected by "low stamina" will certainly draw your attention to the disconnect. Long story short: stamina in games does not approach realism and is unimmersive.
Maybe if you're a robot that wants to know what it feels like to be a human, it's a different story, but as a human, it feels robotic and forced.
That's realism out of the way, but realism isn't my gripe with it, gameplay is. In a game where player A and player B are to shoot each other from any range, sprinting is a good feature. In a game where player A must be at the same position as player B to prevail, it is not a good feature. Imo it's a feature that could turn out to be a defining feature of the game and not in a good way.
Remember that irl, most of the losers escaped most battles completely unscathed. A lot of front line soldiers didn't see combat. That's not the game we want to play.
Warband has a lot of things wrong with it, but the approach in making it was first and foremost, to have a competitive multiplayer game and in that, it was successful. I want to know if that is a goal here. If it is, I don't know how the team thinks that goal will be achieved around the problems that we've pointed out.