if you think about the strict sense of the word "vitality" we think "it's the stamina before tiring after having fought a lot". that's why it have no sense that the "vitality" is shared between all characters on the account. have no sense that a character get tired because other character have fought a lot. if we ignore the strict sense of the word and think about the gameplay, if you remove the shared vitality, we could lvling another character while another is tired. i think this isn't done because the company may suffer an economic impact due to lower sales of xp runes. i think the economic impact on the company would not be too noticeable because most players on the server have already consolidated their characters high lvl and they spend quick the vitality and therefore they would need to pay for more runes. in addition i think remove the shared vitality would be a good incentive for new players like me to start playing and continue to reach the high end and therefore perhaps would have more new players and increase the server population. sorry for my bad english, i have translated parts of my text with google translator.