I don't know enough about what Mowgli posted, and maybe Apple is the worst out of the phone makers, but I know at one point there wasn't a phone maker out there who wasn't suing another one.
Excuse me if I'm mistaken but I don't think that will change what you can file a patent on, or what's enforceable. Just the timing e.g. You file a patent for something but you I some documents/proof that I invented it before you did, so the IP is yours.
EDIT: Ok, maybe I see now, first to file means you only have to come up with the idea but not actually put it into practice? That's dumb, but I still don't see how that changes what's patentable, it still has to be an original invention, something that can work in real life, etc.