It would be great if there support for OpenID in 2.8 but if we have to wait until 3.0, at least it's on the radar.
Since I doubt that OpenID support would cause major API breakage, I see no reason why we couldn't put it in a 2.8.x (probably not 2.8.0, since I'd like to get it released someday).
3.0 has a *lot* of stuff going into it already and it's going to be broken (=unsuitable for production) for many months, I think.
/Janne
