Why not just call it Mystara? Because I discovered something troubling called canon, and despite the constant advocacy to "make the setting your own", I'd feel odd constantly referring to my additions and tweaks and appropriations from other sources as 'Mystaran'.
What things have I / do I plan to mess with that I feel would change Mystara fundamentally?
- The Immortals of Mystara -- they play the role of gods in this D&D setting, but have an interesting structure to them. This is because it is stated in D&D BECMI that there are Immortal Paths available to mortals; any mortal can become Immortal if they get to Companion level and then embark on the paths of immortality. And there are mysterious Old Ones who were revealed in the Wrath of the Immortals campaign intimating that the Immortals (including the really ancient ones like Cronus) are meant to learn something through Immortality but haven't. I plan to muck about with this and change it substantially through my own fascination with gods and mythology and the Cthulhoid pantheon.
- Alphatia -- I like Thyatis as it is, but I had concerns about the rationale on how a thoroughly chaotic nation of mages somehow manages to have an empire - something that requires logistics and planning. Also, given the BECMI game system, it's a given that low level mages learned how to plan ahead with their precious fire-and-forget set of spells for the day, so that must be factored in somehow into the character and habits of all standard D&D mages.
- Some Nations -- Well, not all Gazetteers are my favorites. Sometimes it's the art and the depiction, sometimes it's just that the core concept of the region or nation doesn't resonate, and I want to replace it entirely.
- The Hollow World -- I posted my thoughts on my alternative Hollow World, though it retains to some extent the concept of 'preserved cultures' inside the world. I'd totally rip off all the really cool ideas elsewhere on traveling to a hollow world into my take on it. And I'd add other cultures into that expanded Hollow World concept.
I'm weird that way.