Hopefully,
Arclight Phoenix ban.
But seriously, I think that modern challenger decks are more likely than just a modern masters replacement. One of the problems with modern masters is that it just required too many cards to reprint and wasn't something they could sustain for a yearly
release. Printing 4 played (probably not optimized, but at least played) decks is just scratching the surface of the modern format, and as the meta shifts with new sets it will generate more decks that they can print. This makes it very sustainable for future products.
But please, please, let it at least resemble something that is played. I'm not expecting fully pimped out jund, just a budget mono-red version of burn would be fine.