The heroes have ~2% death probability. (This is 0 medicine, with 100 medicine it is reduced to 1% and with 200 medicine it's below 0.6%. So having a good surgeon in your party really benefits if you're fighting a lot.) Another effect of the patch is that now the medicine is way more effective in changing death probabilities (e.g. you can achieve 50% reduction with 0 to 100 medicine) (Modified by a 30% wounded penalty, meaning in simulated battles it's about ~30% lower.)
A difference between the player-involved battles can be required to adjust the value. We try to find a way where the number of deaths the player witnesses is not significant but also, it's not so frequent that it creates problems for the sandbox. As always these numbers are tested through long simulations (without the player) taking into account the number of adults etc left. Currently, it's closer to the maximum. Depending on the feedback we will tweak the values.
A situation where the death probability is higher for the player-involved battle and player-related characters(companions and clans) can have two "lives", in their first death it is prompted to the player that the character is deeply wounded and have some sort of debuff (and then dying, if the character dies while deeply wounded". I believe some of our players also had a similar suggestion.
Because we tried to keep it as high as possible for you to witness the deaths of great lords but I believe the randomness can take away from the experience if someone you invested your campaign time in just dies by some random simulation battle in the far corner of the map. Even with the complex multiple lives (or progressive death chance as @AndrewArt suggest, how can we "rest" our companions and lords when other than actively keeping them in our party. Not a nice way to interact with our companions or clan members)
Armor is a nice suggestion and gives them another purpose in the game, I will discuss the survival effect of armor in the game with the team. (However, this would also reduce the probability of death for lords as well, making them a bit meaningless, because other than the player everyone who's killable in the battle is a lord.)
On the second note, we're working on a system to reduce the generation gap between the active members and populate the clans with more balanced populations, with that change, I believe the clan's health will not falter.
do you guys intend to change the mortality for player during battles? Like he can die as any other character in game during battles? I think this would be great addition and many would love see that too, it would not only make the player care more for their heroes but would make the game more dynamic as it should with the dynasty system, instead of just old age age and the deep wound as you mentioned
Even with this mod the AI can climb back down but only if the attackers are losing instead of bugging out like without the mod. Some how the one way trick fixes sieges which I never thought I would see the day.