Yeah, I'm definitely looking forward to a new challenge, but balancing this could be tough. The false gods are already difficult to beat more than say 50% of the time as it is(not counting oracle predictions). The one thing that makes them at least somewhat manageable is that there are still a fairly limited number of them, so with a well-designed deck you can at least beat SOME of them most of the time. Even then, for any given deck, there will always be some fg's that are virtually unbeatable(aside from the extremely rare case where you get a perfect draw and they get an unusually bad one). With t500, not only will the decks be even harder, but there will be MUCH greater variety(and especially at the highest levels, these will even be continually adapting to the more popular counter-decks
). It's not too hard to imagine some of these decks being almost completely unbeatable or at least only beatable at all by choosing exactly the right counter(which would then lose against 99% of the other decks).
I'm not sure what can be done to balance this enough to make it at least somewhat possible to win. Having some way to predict what deck you'll be facing would obviously help a lot but unlike the fg oracle predictions, just having a name wouldn't help you any since the decks could be changing every day...you'd have to know what the actual cards in it were. Doing something like that would probably defeat much of the purpose of having t500 to begin with. Adding some new cards might help, but of course this can also go both ways as those new cards will be available for the t500 decks as well. Still something like Mark destruction(at least one mark should probably be untargetable to stop these from completelty shutting down a deck too easily though) or damage per card drawn might be nice as these would cut into the advantages the t500 decks would have. Some other sort of restrictions might need to be placed on t50 decks as well to keep them somewhat manageable, though hard to say what these could be.
In any case, it's safe to say that the days of mindlessly spamming the same CCYB-type deck all day will probably be over