Probably just GT, unless GTA goes back.

Gran Turismo

I agree. If the vgchartz preorder numbers are to be believed, that plan is working.

Nun but GTA6

Gran Turismo.

Maybe Naughty Gods can make a break out game. If anyone can do it its them.

Last of Us 2?

Very well could be with the right marketing. 

As other have said, Gran Turismo. It has always been GT in the PS1, PS2, and PS3.

Any Gran Turismo title on the PS4 will almost certainly hit 10 million or more. Unless in the off chance that Gran Turismo 6 completely sucks and affects sales of future entries.

Considering that Call of Duty looks like it may finally be declining this could be where Killzone steps up. If Shadow Fall is awesome at a time when the most recent Call of Duty offering stumbled badly we may see a lot of PS4 CoD enthusiasts jump ship. However, I don't think it will be Shadow Fall that pulls it off. Assuming that it does very well, I think it's more likely that a future Killzone title would accomplish that milestone.

A future game by Naughty Dog has a strong chance of reaching 10 million sales. Based on sales of pretty much every franchise they've made, Naughty Dog is the most likely studio besides Polyphony Digital to create a title that people go crazy over.

I will also say that if Santa Monica Studio is indeed creating an open-world sci-fi game, that could quite possibly also make a good run at the 10 million mark. Open-world games are the big deal these days and I've noticed a growing interest among gamers for something science fiction-like. Put it in the hands of the studio that made God of War with Stig Asmussen as the director and you've got some serious potential there.

GT7 & GT8.

God of War IV has a chance because GoW3 (MASSIVELY undertracked still) will end up selling over 2 million more units than GoW2 (4.25m) and did so with virtually no bundling, a Q2 release and shitty advertisement, if there's a similar growth from GoW3 to GoW4 it will sell over 8 million units AND then if Sony actually makes an effort with the games marketing, mass bundles it and gives it a holidays release it could hit definitely reach 10m, if everything goes absolutely perfectly. The series has untapped potential because Sony has never supported it like they do other franchises.

Uncharted 4 won't do it, the series will always peak around 6m, even with mass bundling, great advertisement and holiday releases none of the Uncharted games couldn't even reach 7m, the series' full potential has been releaise, Sony literally couldn't advertise UC3 any better or bundle it any more yet it still took 2 years to scrape by 6 million. 10m is out of the question.

LittleBigPlanet has potential to be a lot bigger than it is but the same as Uncharted, I think it's pretty much reached it's full potential with LBP1. Perhaps with better marketing and a holidays release LBP3 could sell 6/7m but 10m just doesn't seem possible.

I hope another new IP can become huge, 10m is a monster target but wouldn't it be nice if that happened. I bet it's a new FPS franchise that does it or comes close, I'm predicting Sony will finally have a FPS to rival Halo next gen.