Ever since the ability to custom-make superflat worlds, the need to nerf slime spawning has been reduced or even eliminated. Back before the rates were lowered, superflat worlds were essentially useless because you were instantly surrounded by slimes.
Now, you can easily make a superflat world high enough to avoid this, and it’s just frustratingly hard to get slimes to spawn legitimately because their rates are so low.
I propose a checkbox option to enable slime spawn rate nerfing, or a 0-1 number to say how much you want slimes to spawn compared to normal spawning (Like the current number implemented for mineshafts). Alternatively, the game could treat swamp slimes different from subsurface slimes, and only nerf those slimes that spawn at lower levels. If you made a swamp biome at the right height, it’s your own fault if you get more slimes than you wanted!
Now, I’m pretty sure the people who use superflat and need mob drops are mostly flatcore players, who my suggestion would screw over… so it would be the best of both worlds if it was made to be an option that can be turned on and off. In fact, Minecraft needs more options in the world creation menu.