The thought was to have the UI best navigated with a controller with can really be seen as for the PS3, but also to accommodate the trend of PC goers as more people are using controllers than not. Still wish they'd make it more mouse/keyboard friendly in some ways by not locking keys and allowing you to bind them to something else.
The game is primarily developed for the PC and a port would actually be more difficult to the PS3 as it would be to any other system. It's not to say that when they get to the point in which they feel the game is mostly finished the bulk of it's changes and ready to port that they won't do a great job, but just answers the question on if it was optimized for easy porting. It isn't. There is no such thing as an easy port to PS3 in general.