I'm A Banana
Potassium-Rich
Well, that's a bit of a different problem!I'll agree with you that players don't NEED to know what abilities work in combat, but I just think it makes the game more fun if they do.
When you sit there for what seems like eternity waiting for your turn to finally get to do something, only to have the DM negate your entire turn with a legendary resistance, that suuuuuucks. There's just nothing fun to me about having your entire agency taken away by an invisible mechanic. I'd rather keep the unpredictable "try it and see what happens" moments to the exploration and social pillars where player creativity can be rewarded much more easily, and where you can immediately just try something else if your idea doesn't work.
I like the idea of legendary resistance causing some monster-specific debuff to happen, which solves one of the major problems without having to get a specific list of permissions. It means your entire turn doesn't feel negated (you can't paralyze the dragon, but it did something more than decrease an invisible counter by 1).
I'm less precious about having agency taken away. It's OK if a player has a turn that's not very effective (or even completely ineffective!). I want combat to be unpredictable, I want my players to engage enemies with creativity and not rely on "I win" buttons, I want them to feel challenged and to try things that don't always work. Failure needs to be a meaningful possibility in a fight, and I don't like the idea of a static "list of don'ts" that just reward system knowledge over actually playing the game.