i think these are good and bad idea's. having to look for quests sounds interesting gives reason to go everywhere like*oh hey a npc lets talk to it i might get a quest*
NM's are fun to do they really are i do hate campers and having to claim monsters so i don't ever actually fight them because it's just not worth the trouble but having a strong boss i can fight for fun is always nice.

now the reason i find them bad. it's simple that isn't what this game is aiming for maybe in another game, but 14 is looking to keep things simple and easy to do i think if you would wanna implement something you should suggest something that ff14 is aiming to be not make them go backwards.

like maybe more fates like odin and behemoth (i know you prolly don't like them it's just an example) like having ultros spawn in the limsa area, or having a jumbo cactuar spawn in the thanalan, think that's alittle eh? well then why not a giant sandworm ( a real one that is popping outta the ground) or a t rex like in 12 or maybe from 8 the mummy thing that was just a head and hands after beating it once, it hops out the sand and you fight its whole body.

or maybe during specific times during the day (or night) during specific weather or some other conditions for nothing other then a vanity minion (because anything actually useful would be against what 14 is aiming for) you will run into the little alien craft from 8 (or something new and alittle more original) just something cool and fun that would be what they are aiming to do and not something that is changing the game back to what they already had.