If a user gets IP banned on the new site, they will be locked out of most things (I'm basing this off the 1.4 site, but they shouldn't bbe very different). This includes the editor. In 1.4, a banned IP can still download and use the editor, but in 2.0, with everything benig integrated in one site, I don't think this will be possible. This would impact things like schools and public networks and libraries.
So will an IP ban prevent a user from using the project editor in 2.0?
It probably will, unfortunately. However, from what I read on the tracker, they might create a way to login-ban IPs (they can't log in, but can still view the site) and might do that for less severe offenses, in which case you can still download the editor.