I've spoken to a lot of people over the years about the Forgotten Realms. The number one complaint that I got was that there were too many high-level NPCs crowding the world stage followed up right behind with the idea that the "metastory," the plot progressions presented in the FR novels and later sourcebooks, made it impossible to keep up with (and therefore run) the developments of the realms. Earlier today, someone made a comment about how terrible I would feel if the 10th Age took off and someone modified it for 3rd Edition.
The real truth is that I don't care what anyone does with the 10th Age in their private time. I have my version of it, and you can have yours. The same goes for the Realms; the Realms you run are YOUR Realms, not Greenwood's and not R.A. Salvatores.
The various campaign settings that you experience are shards, fragments, that do nothing to detract from the core canon. But nor is the core canon really preferential in any real sense. Everything, every addition to the setting that is not canon is IN A SENSE canon. No setting, no constellation of fictional worlds anywhere, is ever overwritten by variation or change. All contradictory storylines, alternate canons, fictions, exist simultaneously, independently,
The same theory applies to things such as fan fiction, fanon, and all that jazz. These things are a semantic web, not a single page of writing that can be overwritten. What's the take away from all this?
USE the 10th Age if you want! Do whatever you want to it! Sink Miles, blast apart the moons, do whatever you like! I don't care, in fact I encourage it! Why should your Arunia look like mine? If anything, if anything I like to think of my own campaigns as Arunia prime. But hell, if you want to find a way to get the stories of your party into the main canon of Arunia prime that's fine too. I include all the parties I run, let them interact with the world and change it and each other.
Go for it!