It was a brilliant shot, interesting to hear Macklin comment afterward how every punch that was landing packed power and were hurting him. You can never be sure if he will carry the same power up in weight, for that reason i'd like to see him fight another couple at middleweight.
I don't think Martinez would fancy it but it might still make the best fight for him financially right now, although he has aged badly, Golovkin doing a number on him, or even Chavez Jr would increase his popularity even more, then he could go up to fight the likes of Ward, or even Froch who Eddie Ahearn mentioned as a possible opponent for Golovkin.