The map is the heart and soul of every GTA game and each sequel has tried to trump its predecessor. The only exception is 2008's GTA IV, which had a smaller map compared to 2004's GTA: San Andreas.
So, when a concept map for GTA 6 made its way online and teased a significantly larger playground, you can only imagine the hype.

As per the image above, the artist conceptualized a map for Grand Theft Auto VI that's nearly three times larger compared to GTA V's. This would give it a land area of nearly 150 square kilometers, which is roughly the size of Miami.
Coincidentally, there are rumors that Rockstar Games will go back and expand on the Miami-inspired setting of 2002's GTA: Vice City for the next GTA game. Not to mention, a map this large would also coincide with the earlier report that GTA VI will have 500+ hours of content.
Unfortunately, outside of confirming that GTA 6 is in development and how it's still coming, we haven't heard much about the game at all.