I've always hated the map memorization thing. To me it destroys the uncertainty and exploratory aspect of a game like CS. I didn't mind it as much in Team Fortress (which is built on cartoonish excess and thus fosters a sillier and less aggressive style of play. Thinking back to when I was a regular CS player, my favorite ever map was a Katamari Damacy style giant room where the players were effectively reduced to the size of action figures and moving around was quite time-consuming. Visually it was quite crude - very basic textures and blocky objects - but it gave rise to all sorts of interesting tactical problems and solutions, while being big enough to make speedrunning impractical.
It's surprising to me that there aren't more procedurally-generated environments for multiplayer; there might not be as interesting to spectate (because you don't know where to look or what to expect), but they'd probably be much more exciting to play.
Due Process is an interesting indie-developed tactical FPS, somewhere between Counter-Strike and Rainbow Six. Its main differentiating feature is semi-random maps (and a unique art direction for this genre).
Every week, the developers proceduraly generate new maps using a theme / tileset (e.g. convenience store, chemical warehouse, gameshow studio), then remove ones that don't survive a playtest. A dozen or so maps are introduced each week and there's no way to choose one, making the pool too large for memorization to be useful.
At the start of each round, teams get some time to look at an overhead view, draw a plan on the map, and decide which of their limited resources to use (night vision goggles, breaching charges, barbed wire, etc.). While the layout is random, different areas on the map will have unique features, like a vault that can be opened with explosives or by pressing a button elsewhere, an arcade room with dim lights and cabinets for cover, or a bulletproof cashier's window.
I've been following the project for years and bought a copy when it entered early access last year. It has a friendly community (for now). Big recommendation from me. https://store.steampowered.com/app/753650/Due_Process/
there isn't really an exploratory aspect to (vanilla) CS. it's a competitive shooter with a small number of small maps, and the weapons are pretty clearly balanced with this in mind.
mods and community maps are a different story, of course, but they diverge quite a lot from the main game.
Additional uncertainty arising from randomness in MP settings reduces the impact of skill (ie memorizing the map) so pvp designs tend to shy away from them, especially in the more esports focused side like CS. There are definitely some skills more fun than others though, otherwise everyone would still be playing Quake3.
Having consistent, memorizable maps allows someone to make progress and improve at the game by learning the map and developing, testing, and iterating on strategic positioning and movement.
Having random maps doesn't encourage that, but does encourage other things like adaptability and just pure mechanics, since you can't rely on having good positioning and map knowledge of course.
It's surprising to me that there aren't more procedurally-generated environments for multiplayer; there might not be as interesting to spectate (because you don't know where to look or what to expect), but they'd probably be much more exciting to play.