Probably not is my thinking.
Reason: it's no use unless there are enough games which support it. And if only one model includes this, even one of the best-selling models, that's still a small minority of the possible purchasers of the game, so it's not clear it would be worth the effort for the developer to include support for this.
Of course Samsung have the money to take risks (because there is a huge business with fingers in many other pies behind their phone division), so they might take a chance. But the flagship is a dangerous device to take risks with, and they are sensitive to the performance of their phone division at the moment. So if they were to do that I'd think it more likely they'd try it out in a separate device, that can be abandoned without damaging their main brand if it doesn't take off (the drawback with that being that it makes it harder to get the critical mass of games behind it). Also right now it looks like they are actually trying to push mobile VR, for which a joystick is no use. So on balance I think it unlikely.
