Thanks for your interest in OJS, and in the roadmap. The roadmap as it currently stands is a little ad-hoc, and we aren't necessarily planning on implementing everything you see there; I've actually been tasked with cleaning it up a bit (and adding to it), so you'll see some changes soon.
I sent your question regarding openID specifically to the PKP team, and it brought up a couple of larger considerations on our end. In a nutshell, our current authentication plugin structure, which supports LDAP and is technically extensible to other protocols such as openID, hasn't been picked up by others, probably due to it's confusing and inconsistent structure. (We also have a Shibboleth authentication plugin, but this had to be developed outside of the original authentication structure as the original did not support implicit authentication.)
We've had enough experience with and requests for authentication that a proper reimplementation is deserved, and likely going to happen in the future; but it's currently a low priority for us, and it'll most likely involve a lot of work, so it's not part of our immediate future plans.
If you have any comments at all, please let us know.