Isn't a current problem with BG3 that important conversations are already tied to long rests, and thus players who don't long rest won't see them?

I think the main problem of what happened to you, Rag, was conversation triggers overwriting each other. At some point Astarion's Bite cutscene flag was turned on, but then soon after Gale's Mystra scene flag was turned on and overwrote Astarion's scene. In my first playthrough, I remember never getting the scene where everyone feels tadpole-sick and Lae'zel tries to kill everyone to prevent transformations. Probably because I didn't long rest until after Nettie, so Rafael's scene replaced it.

I'd like to be able to see all the cutscenes without resting more frequently than I want to. So:
+1 for your suggestions #2 and #3, with heavy emphasis on #3.
-0.5 to your suggestion #1. Your specific example about Gale makes sense because it has a stated #-of-days timer. But for e.g., Astarion's Bite or Gale's artefacts, it should happen at X long rests OR after Y reputation OR after you reach a certain point in the story, whichever happens first.

I'll also add 4.) some cutscenes that don't require sleeping can also/instead take place in the overworld. E.g., most of the dialogues with Gale and Wyll. During a short rest or literally just talking to the companion while exploring.