Most games that I played in this genre had many random encounters, particularly when exploring. When you remove the reward for combat (most mundane combat encounters do not generate loot anyone would care about, some rusty swords that are too heavy to carry around) you make it a tedious chore that will ultimately be avoided.
Consequently, when I go to explore areas, without an experience incentive I will just try to avoid the combat entirely, or quickly grow bored if I cannot. Maybe this game will be better, maybe every single seemingly random encounter will be part of a larger quest, or will have lovingly crafted loot that will make you want to fight just to get it. Maybe there will be no combat that is not part of a quest (and probably therefore not much combat). If there is no experience for fighting then every violent encounter had better be part of a quest.
Presenting the decision to remove xp for killing as a solution to people gaming the system is throwing the baby out with the bathwater, surely some solution could be found to those rare cases that would still leave there being some motivation for combat at times, since the combat system is probably a very big part of the design. There has to be a way to not award experience for killing a quest giver, or simply check and if experience has already been awarded for peaceful resolution, change the experience for killing the people in question to 0.
Simply put quest experience and combat experience together would be the best in my opinion.
Also, I love the stamina and health ideas.
