Power leveling existed long before there was a AE.  Expecting everyone to level up and play the same game repeatedly on different alts is unreasonable.  Some will like that, some will not.  Again, this was and is one of the best things about this game - play the way you like. 
 
	 
 
	As for the rest, I am in agreement with others who have said lack of content updates are what drive people away and this is a normal part of the MMO world. I did want to add that I believe that the host in the linked video was correct - the game desperately needs more endgame content.  There is plenty of pre-50 story content in my opinion.  Why the focus is on low level content does not make sense to me.  I also believe he is right on the money with regard to the pipe dream of the game becoming legitimate. 
 
	 
 
	For me personally, I have run into a lot of people I used to play with religiously on live.  Most of them enjoyed the nostalgia of getting to play again for a few months, then moved on.  I think this is normal for most and should be expected.  It is wishful thinking a game of this age is going to be able to compete with more modern competition on any level.