For me I feel like some of the archetypes are musts, Jagen/Oifeys as well as the late game Ests are usually two sides of one coin that I like to have in the game. Other archetypes it really depends, for me the Cain & Abel archetype is generally a must but more in the sense that I like getting 2 cavaliers towards the start rather than two friendly rival horsemen one of whom is serious the other not so.
So it's sort of a mixed bag for me. Some archetypes are just TOO Japan. Looking at you Tiki, Fae, Myrrh, Nowi, any other mythical creature with the body of a 10 year old that I can marry off to myself or another character. (I'm also kinda bored of the Catria Archetype, like stop giving me a character pining after the main lord who has no shot of being with them due to Support limitations, it causes me too much pain. Cordelia's romantic supports for the most part literally gave me cancer what with everyone kinda being a sort of 2nd prize compared to Chrom.)