'High Casual' has kind of always been a thing though, right? Even before guildfall you would see 'High Casual' tags for RPs in that section. 

I've always viewed each section, at a basic level, as indicators for personal writing ability and progress. That's not to say that Free is solely intended for newer writers or those with less ability, but it's certainly easier for a newer member to view it that way at first. Which is why I think it's only right for the Casual section to have the most range/flexibility when it comes to writing length. 

It's the best section for a writer to grow and improve because that's where you'll find writers of all ability levels ranging from Free to Advanced.