I don't think you've really thought this one through enough.
If Blizzard removed the shop, then it is true that those developer's working on the "paid" content would no longer work on that content. But what makes you believe they would magically just start working on "free" content? You need to consider the impact that the removal of the shop would have on WoW's revenue and how that in turn would impact on the development team.
Ultimately more money for Blizzard from the shop is going to translate into more money available to re-invest into the game. I would be very surprised if Blizzard's return on investment based on dev time spent for shop contents was less than for regular content (ie game sales and subscription). I mean, if that were the case, they'd not bother with the shop at all. So it stands to reason that the shop results into a nett win for the game's bottom line. Which means that they can justify a greater re-investment of funds into the game.
And why wouldn't they? Every single item that is sold through the shop depends on the game's success (which in turn depends on "free" content). And when it comes to tokens, the positive feedback loop it creates to result for more content for you and I should be pretty evident.
So yeah, I get what you're worried about, but I think the reality is the opposite.