Cars Land has been a want back east since it opened at DCA (particularly at DHS), but DCA successfully resisted. The MK version is a way to get around it (even if, IMO, the original would fit wonderfully where RNRC is and be way less impactful on guest experience). Long before the current WDI regime, and certainly a want in the upper levels of WDW park management, at least at DHS - no idea how MK got it in the end, but that's something I'm sure we'll learn with time.
Films have almost always been designed for as wide of an audience as possible (going all the way back to DL's and the Expos' films). This is certainly designed for a much smaller audience (families with young children), probably to address the fact that there isn't much for the young set to do at AK ride/show wise. Not a fan, but I can see the point if it was executed well enough - the problem was that it wasn't.