How does Meek NOT sound southern? That makes no sense...dude is always on southern production doing trap shyt, sounding like Ace Hood. He's not making "east coast" records. By that logic, Rick Ross is making "east coast" records too lol.
There are plenty of NY records NY radio could play but don't. The problem isn't that records need to fit metrics, it's what metrics NY radio is aiming for. They're aiming for black and white women, largely. Drake, Kendrick, etc score so high because women want to hear that shyt. Action Bronson has radio ready shyt, but it's not for the ladies. You could argue men need to listen to the radio more but still...the fact of the matter is that the deck is stacked against non-ladies rap. Fab gets his single popping every year because he understands this.
That's not to say NY isn't often trash in terms of writing songs. They kinda suck in that regard. Think about it: Joey Badass and all them NY cats can't write a hook to save their lives. You can be as lyrical as you want, but you NEED a hook/chorus.