Maple_Wizen wrote:
i wonder if there exists something as a review on mapping theories/opinions/genres in different times, or even a history on mapping
it also helps if you provide any potential fragments of them 
The closest I've seen is
https://pishifat.github.io/. Pishifat has also made several videos on various developments like iNiS style mapping, russian mapping, influence of chinese mapping, wub maps, etc. although it should always be noted its essentially ones persons research.
This redditor did a thing of like looking at key figures in osu,m here they did galvenize
https://www.reddit.com/r/osugame/comments/2v35ea/great_beatmappers_of_osu_part_1_galvenize_the/In general though I think the 'history' is something you learn by osmosis and I don't think I've seen anyone as dedicated to the study although I am. I think its something you learn hrough playing the maps of different eras and getting word of mouth from those that were there throughout various developments in areas you're interested in. Names I heard a ton were NatsumeRin, Skystar, RLC, AngelHoney, DJPop, James, Sotarks, Monstrata, Natteke and in some shape or form you can kind of track a development by looking at what they were doing at what time compared to past.
NatsumeRin is a figure who I figure has been pretty crucial to mapping history from what I've heard from pishifat's interview with fanzhen0019 but why exactly I'm not sure.