Questions and answers.....
It appears according to the tracker (which now seems to be responding again thanks to additional RAM....) that http://tracker.moodle.org/browse/MDL-17725 was not included in the Moodle 2 upgrade scripts, which means that journal tables are apparently orphaned in some way on upgrade as best as I can determine based on info that persons upgrading to Moodle 2 RCs were successful in upgrading, but had no access to the journal activites.
It also appears that there is extensive confusion surrounding the Journal plugin db entry on Moodle.org as it seems to still be in need of a maintainer (IS that going to be you, David, and have you discussed the plugin db entry with Anthony Burrows?) and while there are comments indicating that it won't work with moodle 2.0 on the plugin entry, the posts here are that it does.
Additionally, even if the module works for Moodle 2, the question is how one migrates from a Moodle 1.x with journals to Moodle 2 with journals. That is to say, can one simply NOT convert the journals and then upgrade to Moodle 2, install the module, whereupon the module will work and all the pre-existing journals will function?
So while there is one train clearly southbound, there is another northbound, and the conductors on both trains have inconsistent statements to make which of course leads to tremendous confusion.
It would seem that the FIRST thing to do is tyo update the Journal module entry in the moodle.org db so it is vetted, current and has an active maintainer. Once that is accomplished I would suggest the second thing to do is to make it clear in forums and moodle docs that there apparently IS a transition path for the journal module, as wel as clarify any issues with respect to the db (especially if one is also changing from MyISam to Innodb) and migration.