Yeah, with a thousand planes, it allows us some really great liberties to play with because we can always essentially just say "oh, it wasn't THAT Rabiah, it was the Rabiah across the block. Maybe the one from two doors down."
Yeah, but it ends up violating the basic principles behind the reasoning attributed to keeping canon out of the M:EM, and that is stepping on the toes of MtG canon in terms of potential overlap. Saying that N/1000 are "______ Rabiah" isn't really any more justified than visiting a Planechase-only plane. One day it's possible a number of those Rabiahs might be revealed, no less possible than other ambiguous worlds (Arkhos, Valla, Kaldheim, Utoparia)
Yeah, this argument troubles me. In order for this to be the problem you claim it might one day be, Wizards would not only have to develop all 1001 Rabiahs, but then make those develops clear and distinct to MTG consumers. How many planes has Wizards developed fully? A dozen? MAYBE two, if you're generous on what "developed fully" means? No offense, but are you honestly telling me that in your mind, there's an equal likelihood that Wizards will develop Valla as that they will develop 997 more Rabiahs? Even just mathematically/statistically speaking, it is in fact VASTLY more likely that Wizards will develop EVERY SINGLE PLANECHASE plane than that they will develop every single Rabiah, and that doesn't take into account the fact that they're unlikely to revisit even a single Rabiah for several reasons, some of which Barinellos mentioned. The planechase planes are a lot like the Timeshifted cards in Future Sight. They're a pool of possible resources for creative to look at down the line. Most Wizards products start out mechanically, and then creative decides what sort of world would best fit that. Planechase gives them some starting points if they want them. Rabiah, for their point of view, gives them practically nothing.
No, you misunderstand my meaning. Though you have brought to my attention the fact that there would still be elbow room regardless, but my point is that when you make ______ Rabiah and build it up, you're almost definitely making one that Wizards wouldn't make, or in a way they wouldn't, so there's still that developmental overlap, and yes, they probably won't develop Rabiah (Wizards has an issue with separating certain related factors from the settings themselves. Rabiah can still be an IP of its own, removed from its original incarnation, and Kamigawa's
actual failures that fans still won't overlook all fall into a mechanical viewpoint, and they don't have to come right out and say they recycled Arkhos and Mongseng) and even less likely to reveal all 1000 and thus reveal your fan-Rabiahs are not plausibly among them, but then my point
again is that it is still an ambiguous world from this point on, just as much as other planes (some of which have been admitted to become fodder for future sets, which is up for debate whether that means they have been retconned out of the multiverse or are just abandoned)
Also, as I bounce around character concepts and get interpretive feedback, I am reminded that my creative intentions do not coincide with the M:EM's. If nothing else, the hugest divide is the reluctance to include canon elements, minus
exceptions. As it stands, besides admiration for some of the more popular fan-planes (like Jakkard) and some of the storytelling (anthologies, short stories, one-ofs, etc) the M:EM isn't something for me. What generally does serve me in my creative endeavors is merely other like-minded fans that can offer help bouncing ideas off and can point out to me when a particular detail I've conceived is in fact over-the-top and/or nowhere in the ballpark of plausible considering the parameters. In this case, my parameters consist of characters (Planeswalkers or otherwise) within the canon multiverse as it were, with the only severe stipulation being avoid being smack-dab in the middle of canon (or potentially canon) events. The limitations of the M:EM do not suit me or my parameters, though the community is still one I connect with.