Right now on ru.wp we are running a vote on whether anonymous article creating (not editing!!!) should be discontinued, and it looks like the suggestion is going to be voted down despite the factual evidence presented that most of the articles created by ips is the speedy deletion material. They have of course all kinds of arguments like "creating inequality", "undermining the basic principles" and "nobody invited you to be an admin, please do not complain or quit" which I am sure must be familiar in English Wikipedia as well. Discontinuing anonymous editing at this stage is a no-go, I believe.
I am strongly in favor of anonymous and pseudonymous editing, but I think allowing unregistered users to create articles is a drain on administrator time and should be avoided.
There are disadvantages to editing as an IP, but there can also be advantages. Most of them are of the "no pain, no gain" variety and have to do with the ability to determine truth without knowing authorship. Also, privacy is important for people who have been threatened.
Truthfully, the "privacy" advantage of an IP is overrated. Do you really want people to be able to see that you're operating using AT&T/BellSouth, from Richardson, TX?
But I agree with the "no pain" assessment. If you've always been an IP and never been a user, it's hard to get sucked into the drama.