Technically wow is boring as f... . Most people that still play it, do so as they still have lots of friends playing it. All people i know that still play, just do their weekly stuff and the rest of the week they either watch tv series or manage bots and that's it.
Don't know if you play on US or EU but there are still some servers with ten thousands of players.
From a realistic point of view, of course, even the most successful mmo will one day have an end. I mean compared to todays mmo graphics wow is really ugly. It's a dying cash cow. They could invest some money making improvements to the engine and whatever. Watch this:
[video=youtube;y_CLdGFrjOM]https://www.youtube.com/watch?v=y_CLdGFrjOM[/video]
This is 3 years old, achieved with some enbseries modding. In my oppinion this looks way better. Much better atmosphere. They could do it, if they would want to.
Beside that there is a lot they could to to get the people out in the world, instead of standing afk in cities. Rift for example did a pretty good job on dynamic events, random worldbosses and world events. I know, we had some world events in wow too, but i think there could be way more. Ahn'Qiraj Opening Event was super awesome or the end of the world of warcraft beta, where the burning legion invaded the whole world and you had to defend even cities, that was awesome.