Yeah. Music is classifiable in some sense, but its a hugely complex and multi-directional thing and most 'classifications' really just scratch the surface. And while algorithmic recommendation services (lastfm, spotify, etc.) can be nice for a while, actually people are complex and always change their views and interests, so they are never always going to give you what you want.
Personally for my own collection - I have a loosely interpreted directory structure that I've evolved that is basically 'continent and/or genre'/'artist'/'album (with year recorded at the start if I have lots of them)' that works well for me and I don't have to constantly rename everything I download (theres some less-sorted directories of things I don't listen to much within this).
For searching, tagging and playing I use foobar2000 (unfortunately still windows-only) because it has plenty plugins which handle everything from tagging (eg. from discogs and freedb), through to searching (keeps a constantly updated and strongly index media library, which can be searched from a range of front-end UIs) and information finding (getting album covers, lyrics, artist biographies, etc. and displaying as you like). I don't do lots of retagging, but I do find it useful sometimes - for instance I have tagged some of my more listened classical music by composer and performer separately, so I can look at it from either direction when I want to.