An interview on Dutch site InsideGamer talks with Yves Guillemot, and the Ubisoft CEO reveals the new PlayStation 4 architecture allows them to develop games with the PC as a lead platform, since it will now be far easier to port to PS4 than the PS3 (thanks VG247 via Player Attack). Here's a Google machine translation of him explaining how the Xbox 360 being lead platform was a problem for Ghost Recon: Future Soldier, and how their upcoming Watch_Dogs will benefit from being developed on the PC:

We have, in my opinion, but a game that had really had problems with a port and that's Ghost Recon: Future Soldier. The PC project could be better managed. But with the other brands there is a lot of time and effort in which all platforms have the perfect game.

We also expect fewer problems with porting games to the PS4 than the PS3, which had a completely different infrastructure. It is now easier. Previously, we developed first games on the Xbox 360 and which were then translated into the PS3. It took a lot of time and money to make that port. Now we develop from the PC and which versions are translated into a console like the PlayStation 4.