I really can't see either the PS4 or Xbone having a 15 million seller without a new multi platform title arriving with COD level popularity. The biggest series the 360 has to offer isn't even hitting 10 million anymore, and i'd be surprised if the next Gran Turismo sells 10 million on the PS3 (saying that, if the PS4 is popular enough i could see a Gran Turismo 7 hitting 12 million). If i HAD to guess on a game hitting 15 million on either of them it would be the next COD, on whichever is the better selling console.
The WiiU could go either way. If it manages to build up an audience on level with the current HD twins (which i doubt it will) then sure, we will see Nintendo with multiple 15 million sellers. I don't think anyone is going to debate the strength of some of their IP.
The PSV, lol no.
The 3DS will likely have many less than the DS, but has a chance for some. I'm not convinced Pokemon X/Y is going to hit that mark, but it's possible.
