Why should I re-subscribe?

Long time wow player, that is interested in playing wow again but I just cant seem to find a reason why I should subscribe. I quit several months ago when my guild was 13/14 SoO normal. Coming back now, it would be fun to kill garrosh, but that cant be the only reason for me to come back. So /r/wow please tell me why I should re-subscribe and pay $15 X 8 months until the expansion to come out? What value do you get over the next 8 months? is there some new content I or other than would be paying for?