Also as far as rumors go - it makes literally no sense to cancel the Dopey Challenge. Not only do they charge a premium over the cost of all 4 races individually, it is also the first to sell out. The one at risk in my mind would be the goofy. The addition of the 10k added a reasonably large number of non runners aspiring to do their first race - very few people are willing to travel for a 5k, but will have no issue doing one if they're already travelling for someone else. Prior to Dopey the 5k's were small and very low key. The vast majority of people I meet running the 5k's are Dopey's. The 10k is a bit more balanced, and the half and full you get your good mix of goofy's and single race runners.
I don't think the logistics of Dopey are that much harder than that of goofy minus the vast increase in the size of the 5k. And yes I will admit being a corral A runner we finished before hte last corrals even started in the 5k and 10k, so waiting for those buses was a little chilly - world's smallest violin right here. Note to self pack sweatshirt. But that was it. Hung out in the handicapped tent to stay out of the wind and ended up helping racers switch out of their wheel chairs, it was actually a really fun ending to the 5k.
So for people afraid this is Dopey's last year - I really wouldn't sweat it. Its making disney plenty extra in race entry fees. In addition its causing you to stay 2 days longer than you would have (at minimum) if you were going for Goofy - so there's even more $$. The challenges have been the biggest change disney implemented over the last year giving basically every race a challenge component which sells out faster than the individual races. I see Dopey sticking around for a while. The one I would worry about however, is Goofy...because running wise its not really any harder than the goofy challenge - so most people who would be willing to sign up for goofy, would sign up for Dopey. The killer is waking up 3am. Every. Single. Morning (Groundhog Day anyone?) And personally I love the Goofy challenge far more - the shirts are way better. I'm just a bright orange person. Really you had to see me skipping to get the bright orange shirt.