Gaming is fun, and fun is for everyone
You under estimated the number of players who didn't like mixing the settings.
I'm super doubtful on how much settings and lore even matters to the core MTG audience. I don't think they dislike it in general, it's just secondary to actual card mechanics.
Anyway, I'm not sure how many takeaways one can take from this dev post. It doesn't really provide much hard evidence of much, beyond generic statements like "More polarizing than most sets," or "It's selling very well."
Beyond these probably not being premier sets anymore, and it being unlikely for there ever to be a true canon MTG-D&D crossover, everything else seems very much in flux. This card set doesn't even really "mix the settings," so I doubt they'll move even more in that direction.