I mean its a cool feature, glad Blizzard only said it comes once with buying the expansion (You must be desperate if you buy multiple expansions for multiple 90s)
But when I read they might add it to the Blizzard Store.. I almost hurled. If Blizzard does this they will be saying a big "Fuck you!" to old content and low level content in general. I'm hoping they don't add it because there is a lot of content there that Blizzard can advance upon.. and I'm not saying remake it they learned from Cata.
But at least make it enjoyable, I am especially nervous about new players getting a free 90.. I mean some players will want to quest, but most will skip 80% of the game and never experience it.
I hope Blizzard doesn't add instant 90s as a store feature AT LEAST for new players.