I thought his take on Melee this time was better than usual.
For the injury bit, I have seen a some players affected by injury, a few hgh profile, a few local. Some quit, some take breaks, some show up wearing wrist braces. I've seen doctors at Smash tournaments doing panels on how to keep your hands healthy. Most of it is just from playing Smash/video games constantly in general, but I do feel like it would be less prevalent if we didn't have to press R every time we touch the ground, or constantly make that pinching wavedash motion.
I also think 5 does look good in that regard. Lower landing lag without input, options out of dash so we don't have to do anything weird to get that. Still looks like it has too much Smash 4 in there to have a great combo flow... but I'm eager to try it anyway.
As for the 'quitting because it's too technical thing', imo he's overstating it. Yeah, that does happen, but it probably happens way less than people giving up because they're salty about skill gaps. You can't get rid of skill gaps without punishing those who do want to learn. Also, it feels way scarier in Brawl and 4 than Melee/PM. At least in the latter I can lean on johning about tech skill more.