I agree with all the problems brought up here but I don't think making people pay for accounts fixes anything and just creates a bad new user experience.
Maybe we should limit reach if there's too many low upvote posts by one user within a set time. Although it still creates issues with people creating tons of accounts.
It's already limited how many transactions an account can make and it's depending on how much SP the account has. I don't think that's a big problem, it's just a question of adjusting the limitations to be suitable for the needs of the community.
The real problem is that we can't give away truly free accounts because they will be hoarded immediately. Somebody has to pay for them. So the question is: who will be the payer? I think the fairest solution is that everybody will pay for themselves. But of course we will get a lot more users when there is a way to donate accounts.
My proposal of SPOW-mineable accounts is basically just a way to make sure that steem earned by posts is used to create new accounts instead of something else. Part of the inflation will be marked as "can be only used to create new accounts".
Maybe we could have a community vote or something? So the introduce yourself post would be something that based on either not getting a flag or getting enough upvotes would be how new accounts are approved. The only problem would be could the community keep up?
The namespace would be also a problem. If a new user registers an account but makes a bad introduction post, they won't get any SP but they still have the name of the account. That means nobody else can't get that name anymore.
Also different languages will become problematic. Not everybody can write English.
And not everybody even want to introduce themselves, they are not interested in blogging but just want to have a cryptocurrency wallet.
Namespace everyone is familiar with due to Reddit, Yahoo, etc. having the same issues. Wallet wise I guess we could say pay a small amount or post.