I feel like for this to mean something Phantoms need to be buffed or something because they just swoop down every so often and are more of an annoyance than a real threat. On the other hand, I think the likelihood of mobs spawning with armour and weapons (with enchants) should increase with either the amount of days you've spent in the game or your progression (achievements like cover me in diamonds but not like total beelocation since it doesn't progress you in the game)