I really really didn't expect all this negative feedback about a game delay. Unless you are planning on dying in the next few months, 2 months is an insignificant amount of time. It isn't going to cost you any more and the game is only going to get better. Just be a bit patient. Look back to some of the great games that people play, at this point would you care whether skyrim came out in November or January? No, cause it has no bearing on the fact that it is brilliant and you can play it absolutely tons.
Mr marketing and advertising has just written what everyone wants to hear and stuck an only slightly relevant job down to make it seem like he knows what he is saying. I am not personally attacking the guy but everyone could tell you that if you have to delay something, making an excuse of it needing work will help keep people happy. But you need to actually working for R* to call their bluff cause none of us know the truth.
Finally, PC gaming is much harder to develop for with the thousands of hardware configs and different software people run. You also have to factor in the higher quality graphics they have create assets and code for. Plus the in game film maker that worked quite well in gta v.
I have plenty to do in the 2 months between the release dates, and I really hope this is a great port of an already great game.