If I may, then, I'd like to offer that such a thread be started in Chit Chat & Miscellaneous. However, I'm inclined to think that I (or another JREF Team member) should be the one opening the thread, so as to set the guidelines within the thread--otherwise, we could have spill out. (and I mean negative spillout).
For example, one thing would have to be whether we'd want a real thread--one is really ranting, and is serious about it, or whether we'd want a humours thread. The former is probably what Pachipro had had in mind, and what ASHIKAGA has in mind too.
We would have to follow the Forum Rules (especially #1), and that would mean no personal attacks, or statements coming close enough to such that the object of a negative statement/claim could feel as though they were being attacked in any way. It would also have to follow Forum Rule #3 (Keep Your Posts (Family-)Friendly).
I would also disagree that it would be positive-in-outcome to allow commenting on the rants both within the thread or on other thread starts about a post within the thread. It would possibly be productive to start a thread about a matter or issue which had been the cause (or source) of the rant, however, on a thread in the correct area for that subject matter--for the example the pros and cons on 'working over time on what is otherwise a national holiday' or such.
I will strongly consider opening and sticking such a thread in the very near future after waiting a bit longer here to see if there would be any objections from the JREF Team, or from those who wish for such a thread. I do strongly reason that it'd be best to let a JREF Team member open that with a explanatory note and guidelines.