I think you need like...a lot of extra videos, not just a few immediately before launch.
Releasing videos would be rather counter-productive at the moment. He's working on building back the engine proper now that he has performance going strong again, but the game isn't back to where it was before. People that hadn't been paying attention (most people, present company excluded of course) would think he'd actually wrecked the game and been piddling around for the past two years. He needs
something new to show - something that makes it quite obvious that forward progress is being made.
This is all said without mentioning the fact that it was the excessive dev video work that helped push him over the edge and gave him a mental breakdown.
Now - all of that on the table, I do agree with you on some points. If he had something impressive to show, and could get videos out with minimal editing in a short period of time - I'd say he should
absolutely post a few videos up, and I'm going to strongly encourage him to. I'm sure that after he releases Beta we'll be seeing a lot of videos on YouTube, too. He and Scott Manley (prominent YouTuber) met up one year at GDC, for instance, and he's planning on giving him a Beta key - and will probably release press versions as well. I think we're on the right track to getting Limit Theory some visibility.
That Which Sleeps recently bombed hard and publicly, in a way slightly similar to Limit Theory (not the same, but the whole 'dev leaving and coming back after ages promising loads had been done') and so I think people do need way more reassurance than before - the best way to do that is show stuff happening.
Aw, yes, I was following that project closely and was immensely disappointed after they dropped those updates on the situation. It had such promise.
I'm still hopeful something may happen eventually, but... realistically, it's hard to expect anything more.
Josh has been posting images, though. Here's a few.
If you're interested, he's doing weekly devlogs
here. I really don't think bi-weekly video updates are something we could consider, unfortunately, seeing as the previous update videos often chopped nearly a week off his coding time.