Power to the people

Right on!

For this to work

You would need one hell of an editor. Before a lesson could be written someone has to sit down and figure out how the subject breaks down and what the individual lessons should be on. The editor, preferable the same person who broke out the lessons, would then have to proofread the lessons submitted to make sure they actually covered the topic assigned and didn't make assumptions in knowledge. Sites like K5 can survive if the man in charge has other things occupying his time and attention, your proposed site would be absolutely devestated by the same absence. For that reason I suggest the editor in chief (or whatever you want to call him) be a paid position and have the same expectations of attendence and job performance as a regular job would have. Volunteer hobbyist have a habit of eventually getting bored and moving on.

The other vitally important thing is censorship. Your site would have to make quite clear that the lessons are NOT a chat forum and any comments even slightly offtopic will be moved or deleted. Consider K5, if this article makes it out of the queue I expect at least 50% of the comments will not be related, or at best very very loosely related, to the topic. If this was allowed in a lesson readers would get bored and leave or spend they could use to learn sifting through 'how's it going' type crap instead. You could of course have nonlesson forums for chats, but whoever ran the site would have to be a censoring dictator in the lessons.

I don't understand spending all that money for a fancy shot ... when this ain't nothing that a good coathanger or a pair of steel toed boots can't fix it.

I think that ideally, every module should be accompanied by the following info:

contents - what the module should teach you, preferably described in generic terms so that complete beginners can see where it fits into their overall study goals

more contents - a specific (but short) list of what's in the module (eg. 'introductory grammar' for a language, 'file access methods' for programming, 'deep frying techniques' for cooking). There's no reason a very basic module couldn't also be a useful reference for someone experienced in the subject.

pre-requisites - what you should already know before beginning this lesson

side requirements - what you should be studying at the same time as this lesson

estimated time for completion