It would be really cool to find the sweet-spot between "twitch.tv-like free-for-all that eventually devolves like medium did" and "site run by select group of individuals that eventually develop a clique" - somewhere that lets enough people post so nobody gets too burnt out, but not so many people that it's just like the million and one other videos of this sort of thing on YouTube.
Basically find the balance between supply and demand so that most subscribers have watched all of a given uploader's past videos, while new users won't feel like they have 1000TB of old content they need to go through to catch up.
It wasn't until I read WestCoastJustin's comment (https://news.ycombinator.com/item?id=11670868) that I thought that something like this might be run as a top-down project with a chartered (for want of a better word) set of specific contributors - my initial interpretation was a social approach, where many people could upload videos and become well-known for their experience in specific areas (but still following along with a set of themes specific to your site).
What might be really cool is a system of competitions/incentives/rewards that encourage people to submit high-quality content, along with eg funding small events/hackathons/the like. That sounds like it would be a lot of fun!
Besides DevOps and infrastructure I would also highly recommend you add "enough focus on current programming languages to fully comprehend devops from the dev side of the fence" - focusing on how the engine works without driving the car and seeing the scenery will be boring :D (Translation: go maybe one or two steps beyond TodoMVC, but leave it at that. Then people's appetites have been whetted - which is kind of the idea!)
On a slightly less positive note, this concept reminds me of a service that provides screencasting services for programmers; one of the founders (who may have (had(?)) some mental health issues) who began accusing a video uploader of certain actions in a very confusing way. Not drawing any conclusions myself; the comments (go to your HN settings (username, top-right) and turn showdead on to see them all) are over here: https://news.ycombinator.com/item?id=10486476
I first learned about that service a few months before the linked events happened, and I'd initially filed the site away as something that might potentially be fun to use; I'm not sure how I would proceed to use that service now that this has happened, because I wouldn't want to be caught up in a similarly bewildering sequence of events myself.
Since DevOps is a very interesting subject to me, a site like this would fill a definite hole. I can't promise I'd immediately be able to use the site myself (for current specific reasons that may for all I know have changed by the time the site is up) - but the idea sounds really cool.