So only maps of modern age sets are legal.
But don't big tournaments restrict map choice already?

In modern age, yes.

Big tournaments usually restrict maps, I think to modern age. Although, before this addition, there was nothing in the rules governing maps (outside the retirement of "non labeled" maps)

I see now, so they already added the modern age limit to the maps as well.. That's a shame.. Thanks Jawapimp!

Depends on the tournament and, possibly, even the individual events at the tournament.

For example, at GenCon, Worlds is typically limited to the 10 (or so) most recent maps. But some of the other events at GenCon allowed players to use other official WK maps (provided the players had them, of course).

Ah, I was thinking about GenCon Worlds and knew there was some sort restriction. Thank you for the clarification.

Personally at my venue, if it's a map, it's good to go (for the most part... cough street fighter cough). I can't imagine many venues being super strict on maps, outside of the more "troublesome" ones like Bizarro World.