I think people are going to keep running their games like they want and the only thing that will change is language choices and characterization WotC decides on in the future. Consider that an adventure where orcs are coming down from the mountains and slaughtering villagers has orcs that are evil because they're slaughtering villagers, not because they're orcs.

Honestly the only thing this complicates is the classic dungeon crawl, but even then old school players never seem to stop talking about how they made allies with this monster or that group in the dungeon, etc. Which means even in a dungeon there's a capacity to treat intelligent creatures with free will like... Well like intelligent creatures with free will. And not a walking bundle of hit points you have moral license to kill because they don't look like your PC. Oh and Rangers. Rangers probably need to drop the classic Favored Enemy thing. To be fair, it's kinda sucked since it was called Favored Enemy, so replacing it with a better feature would really work out for everybody.