[@Odin]

I am very well aware of Myriad Reality—in fact, it's almost as if the suggestion was written with that in mind. However, you seem to be a part of a collection of people that dislike it for its ARG-esque style (or at least its location on this site). While the Free category [i]does[/i] state "involving one-liners, few-liners, speed-posting," it also states "and for anyone who doesn't want to have to worry about standards." This line attracts a great deal of low-effort posters, and (at least for Myriad Reality), the standards are very high—they happen to turn away many individuals who do not meet them. Casual, on the other hand, mentions "enjoy writing at least a paragraph or two, character development, and some depth." While speed posting does not match the first qualification, it does match the latter two, considering character development is mostly performed irrespective of post length, as well as depth. "Grammar and spelling are encouraged" implies that it is of significantly less consequence in Free. So for that one in particular, it aligns more with Casual (or Advanced, if you want to chase that rabbit trail) in every qualification other than post length.
The main point of this being that if you want to change the qualifications for each subforum to post length, feel free to lobby all you want for it, but I don't believe that it is correct to use roleplays that match a majority of the current descriptors as evidence that there is an inherent problem with the system. Though I would like to point out that at the end of the day, it is Mahz, not the users, who decides what is interpreted as what on his site.