Ahri's popularity reached a peak at the end of season 3 before her rework... it's probable that there were a lot of people 'maining' Ahri around that time because she was so FotM. The rework made her much more dependent on hitting her E, which took a lot of that strength and subsequently popularity away.
Personally, I've played her since the day she was released. I knew well before then that should would be my favorite champion, and acted accordingly. The only reason I don't play her now more is because Jinx came out and I enjoy her a bit more, and shifted to playing primarily ADC. Ahri's still my bbgurl on mid.
I can't think of a reason to max E second. It's typical for utility-based abilities on any champion to be maxed last, and that's no different for Ahri. Your E is going to be useful no matter how many points are in it; your W needs an investment to get going. Plus, from maxing E all you get is damage and CC duration. If the cooldown reduced on level it might be a different story, but as it is while the duration is great, chances are if you land an even a level 1 E with your ult up, the target is going to die or come close. You gain little by maxing it, and risk not having enough damage on W regardless of if you hit the charm or not.