The G4 seedings were released and I'm pretty sure this is an accurate representation of the actual top 16 in Smash 4 right now:
ZeRo, Leo, Larry, Ally, Void, Nairo, Komo, ANTi, Aba, Dabuz, R, Kameme, Ranai, Marss, Salem, Tweek.
Of course the ordering of the seeding isn't necessarily entirely correct, but if someone were to list the top 16 smash players right now, it'd look pretty close to that, and all of those 16 are going to be there. G4 is amazingly stacked.
The character diversity amongst the top players is fantastic. It just so happened as the game progressed that there are very few repeat characters among the game's top players. Judging by that list and those players'
most played characters:
x2
x2
x2
x2
x1
x1
x1
x1
x1
x1
x1
x1
We will probably see Sonic from Komo and Olimar from Dabuz, and might see MK from Leo and Bowser from Nairo. Counting those, the top 16 players are repping a total of 16 different characters. The fact that the top players can and have have spread themselves out over a sizable portion of the cast is something I really appreciate about Smash 4.
For that matter, Japan's top player character diversity is pretty crazy. Going off of the JAPAN Power Rankings, their top 25 players main 22 different characters.