Something that has to be said and very well understood:
Good music is not defined by some gold standard such as "ATCQ/Nas/PE-type of thought provoking hip-hop". If all music was like that, hip-hop would be very boring. Good music is music that manages to serve the purpose it was created with, i.e a crunk song is good if it is crunk, whether it contains the whole Oxford dictionary in it is totally irrelevant.
This is why I say that it is still easiest to find good music in the South - because you're typically looking for some crunk club shit with good beats or some dark gangsta shit and these are not at all hard to find. Supreme lyricism is not, but it is not what you would look for in a southern rap record.
P.S. What IMO is the reason why the South is on top is that it somehow manages to reinvent itself over and over again while still keeping the sound distinctively southern. While all other regions started biting the South which is BAD. If you take a look at the not so distant history, you will see that the South was first on top with No Limit and Cash Money in the late 90s, than it lost steam around 2000-2002, but the crunk came out in 2002-2003, it revived and reinvented itself, and did it several more times since than with trap and snap music. In that period nothing else new and fresh came out except for hyphy (which is heavily influenced by southern music, let's face it)...