I don't get why so many people have problems with stamina in the first place. I mean if they want to see what true stamina management hell is like they should try the DarkSouls Series. Especially at the lower levels when you don't have or can't add extra stamina and your facing multiple enemies at once. I think most of them would rage quit within the first 10mins.
As for this game yes i agree it can be annoying at times but the majority of people that complain about it hardly use their brain at all. i.e when they are being chased they run in a straight line untill stamina has fully drained and then get swarmed by the mobs chasing them and are unable to dodge or counter. when they should be looking at the environment aground them. looking for advantages to use. Only using so much stamina to run then using the rest to attack or evade.
i understand the stamina regen is quite slow to refill but its still manageable and maybe Irongate could either tweak certain foods or add new ones to boost regen instead of the max value.

Stamina for creatures could become problematic and would also be a stress on the system to keep up with it all as it has to tally not only your stamina but the creatures stamina's aswell but then thinking about it creatures that are running are not sprinting therefore not consuming stamina. I don't know i think it could just become one massive headache for Irongate.