I like the idea of a controlled, set-specific meta, to create some interesting and perhaps never before seen metas, but it also kind of seems rather specific of a request to add to the game.
I would also argue that duels was an attempt at this, with having select wild sets brought back to use alongside current stuff (they teased this mode to use your old collection). However, the obvious problem here is that duels is pretty bonkers and not exactly what a standard meta ever looked like.
I don't have the numbers, but I would imagine another game mode on top of everything else would spread the playerbase too thin, but I could be wrong. It would be an interesting in-between standard and wild that could be a lot of fun.
I doubt they would implement such a thing, but I'm down to give it a try. :)
I do agree, but the truth is new game modes are constantly being added these past few years/months and some of those don't feel very fresh. Battlegrounds sure was great, but I question everything else. Classic is almost pointless given what they could have done instead, its just a way to give players the chance to play with unstandardized classic content since they changed that, and duels is a game mode to play once in a while. These game modes are already spreading the player base but they do need fresh content that uses existing content to keep these players in the game. Expansions by themselves don't do enough, which can clearly be seen by the declining relevance of the game