> The second issue is what you described, the mixing is just bad, sound effects and music are much louder than dialog making it impossible to comprehend without subtitles.
The trend of mixing sound effects much louder has been in vogue for longer than star wars exists and not a lot of movies drown out everything in super loud music (Christopher Nolan films being exhibit number 1 lol). I think part of the issue stems from the audio not being adapted for home releases. There used to be special sound mixes for VHS, TV shows and even DVDs (as stereo version of the 5.1 track) that lowered the dynamic range and made everything fairly clear even on your 70s CRT TV speakers.
Nowadays sound engineers probably marvel at how nice and crisp their work sounds on a studio kitted with 1 million worth of audio gear and call it good enough for playback in all systems. Add some directors wanting more "natural" dialog requesting actors to speak softly and the deal is sealed, only the 0.1% can watch anything without subtitles.
I honestly think the solution is for the industry to adopt a standardized audio gain control solution. The only reason we didn't get that in the past was because implementing such things on consumer gear was far too expensive (it was far more cost effective to just pre-process it and deliver the low dynamic range mix right in the medium, with the advantage of the possibility of a custom tuned mix). Today's TVs all have some kind of audio normalization functionality but they are all kinda bad (they alter loudness balance making everything sound tiny, a proper solution requires proper equal loudness contour compensation) and not suited for sudden and constant jumps of volumes like in movie action scenes. It also doesn't helps that every manufacturer does it differently.