So, any progress on this yet? I haven't made any new copies of my world, so I haven't had this glitch happen since I last updated this, but since the disable autosave option was taken away, copies are my only way to test things and help people with achievements. I don't want to do this in fear that it'll break my world.
I'm going to give my own testimony on this, as it affects the Xbox One Edition as well. Outside of spawners, Nether mobs are practically non-existent after you go through a Fortress once. Also, the amount of hours I've spent over the last several days searching for wolves and ocelots (just for a couple simple achievements) has been ridiculous. I finally found the five wolves, but have not seen a single ocelot. I'm seriously wondering if they even exist (I know they don't spawn on peaceful). This terrible spawn rate of mobs is making some aspects of the game impossible.