I also wonder whether this will just be one of many breaking points that wasn't or if it will mean something more significant due to the symbolism of putting a Cars land so front and centre such that it dominates two of the original lands in the park.
Personally, I have been surprised at how much this announcement has flicked a switch in me toward being done with them. I'm not willing to say it will be a terrible mistake and they'll regret it, because I don't really know if there are masses out there clamouring for the Magic Kingdom to be re-made into IP-lands. I was already pretty over WDW due to the costs and over-complicated planning processes, though, so this feels like a final push toward finding it hard to imagine I would ever be able to justify the time and money it would take to visit the place again. Maybe others want interchangeable parks that allow them to step into different IPs, but that's not what got me interested in Disney parks.
That said, I would visit Disneyland again if I happened to be in LA and Disneyland Paris is a pleasant 2-3 hour train ride away from where I live, so if the person I usually catch up with there while she's visiting family in Paris suggests it, I am sure I will go. I can't for the life of me imagine a circumstance where I would spend precious vacation time and bags of money to fly to Orlando and enter into the worlds of Cars, Tomorrow, and Fantasy, or however it ends up in coming years. I'm honestly curious if I will switch back to being interested in going again.