The first experience for new users to the English Wikipedia
We need to encourage more mentoring, but in a very friendly way. It needn't be mandatory. However, an experienced editor can mentor a newbie without asking permission, by posting on the newbie's talk page. I've done this several times. A majority of the ones I singled out for special attention wound up leaving the project after awhile because they wouldn't or couldn't conform to policy. But, I saved a few well-intentioned editors who probably would have been chased a way if I had not stepped in.
What new users need is for one experienced user to look at their idea for a new article for a few seconds before they sink hours into struggling with the markup etc. It's pretty easy for an experienced user to estimate the likely problems with notability and so on. The most important determinant for the new user is what conditional branch they happen to be on. Someone who wants to write about their garage band is in a completely different class from someone who wants to write about an obscure, but well-referenced mathematical theorem.
Our current method is to use late intervention. Let the new user blindly assume their new article idea is going to work, when in all probability the new user knows nothing about Wikipedia's content rules yet. After the new user has committed possibly hours of work under the expectation of success do experienced users happen by to provide "mentoring" by festooning the new article with ominous template messages.
I think that's the best approach that has been suggested, because of its simplicity, and because it engages a new editor with an experienced one. The current approach (instant deletion of articles that will likely never be kept) turns new editors off of Wikipedia. But simply allowing hours or days for the same article to be avidly worked on by the new editor, and then summarily deleted, is even more harmful. Having new editors start an article in their userspace, and then ask at a New Articles Noticeboard for feedback from helpful and welcoming experienced editors (and not experienced deletionists), would be ideal.
How would new users know to go to the New Articles Noticeboard while they're working on their first article? Would we just force every first article to be created in userspace and moved into mainspace only by an experienced user who has worked with the new user? It seems workable, but not everyone would agree that it's a good idea.
What if we created such a noticeboard, but didn't force people to go to it, instead just strongly suggesting they go to it when they create their first article? (And, if they didn't go to it, suggest again when the article gets deleted and, as above, moved into userspace.)
I'm sure a template could be created that notifies new users, when they try to create a new article, that they can/should/must start in their user space first. Guidance and instruction is desperately needed for new users, otherwise they will continue to be frustrated by the complexities of Wikipedia, usually never to return. Whether it's required, or suggested (with help in doing it), something has to be done to help new users who create articles from being permanently frustrated by Wikipedia.