It makes perfect sense to me. Having the meta-achievement without any individual achievement means that you, the player, have explored the whole continent but your monk character has not explored a single area.
Also, meta-achievements is ok to have it as account-wide only because it allows people to earn the meta doing individual achievements with different characters, and at the same time making meta-achievements account-wide does not make you lose information about what you have done with each individual characters because with just individual achievement it is enough. In your example does not matter if Explorer of Eastern Kingdoms is account-wide, character-wide, or even not exist, you are able to tell if your monk has explored the whole Eastern Kingdoms by looking to each area achievement.
Also, you are wrong about your monk, your monk or any other of your characters does not have Explorer of Eastern Kingdoms or any other meta-achievements, those achievements are account-wide only, that means the achievement belongs to your account and not to any of your individual characters.
It is simple. I want to have achievements that give me information of what my account has done and what my characters has done. With the current achievement system I have exactly this. If you just want to only see account information the solution should be an UI optioin to hide character information so you can select it and pretend character achievements does not exist.
The UI option is simple, it means to have an option to choose between seeing character achievements, account achievements or both.
If you choose both the achivements will be just like today, no changes.
If you choose account achievements then it will exactly as you want. All achievements will be like meta-achievements, so as long as you have earned the achievement with one character you will see that achievement completed on any character but the current indication that said your current character has not completed it will be removed. Also you wont receive notifications for earning the same achievement in additional characters. So in your monk an achievement that you have completed with your monk and achievement that you have completed with other character will look exactly the same, a achievement that you have complete.
If you choose character achievements then the game will work like now but only meta-achievements and achievements earned by the current character will show as completed. So in your monk an achievement that you have not completed by your monk and achievement that you have completed with other character will look exactly the same, a achievement that you monk has not complete
Personally If I have the option I will choose to show character achievements only in my main and account achievements only in any other character. I don’t care about doing the same achievement again with my alts but I prefer to complete all the achievements I can with my main. I have achievements that I have only completed with alts and those are in my to-do list to complete with my main.