1.The dominantly pre ordered console is PS4 this means there will be A LOT of xbox players getting PS4s, i have Dark souls for my box but i dont have a ps3, i want to get DkS2 and play it online, but i am not paying for both PSN+ AND XBLG so im going with PSN+ this means my DkS2 experience will be limited, same for many other people.
2. This is a good way to bring in more money for FROM, people will buy the next gen versions of the game over current gen even if it has just a slight quality increase, so it goes hand in hand with the next gen sales and the sales of the game.
3. Longer lifespan, current gen consoles will have the plug pulled on their servers soon and online play will be impossible, a next gen port is a good way to make the game live longer until another souls game comes out.
The downside however would be that if you dont use PSN+ and you decide to go with PS4 you need to pay for online.
I know not everyone will agree with me here but i feel like theres a lot of good in making a port.