I'm more or less with the OP about the current status of Myth, at least as far as adventure mode is concerned. The switch to modules definitely seems to have fixed story mode, but freeform/adventure mode doesn't really work. The interrogate system for fighting a boss to actually be able to progress your characters,though a great concept, was executed in a manner that is clumsy and awkward, and it isn't even available as an option until you've already to Journeyman rank. As far as the other options for fighting a boss, I dislike the idea of choosing to do the same single quest over and over again to be able to fight one, and I really hate the idea of "just like, you know, fight one whenever you feel like it, man." Far too arbitrary. The game needs an actual system for it, and it needs to be more elegant the Journeyman only system that is currently in place.
Can add but will just say... It was a rushed product and the fact they jumped onto another product before finishing their first tells me much... I await the journeyman as maybe it will fix some/most of the issues but till then no $$$ going their way...