The whole conference starts off on the wrong foot - its stated aim is to find a way to make licensing costs 'reasonable'. That means it won't even get to discussions on putting an end to the patenting the obvious, or ending patents for ideas* altogether.
Also, just the big boys? They'll just want to get back to the patent cold war era: All the big guys have more than enough patents to countersue so they'll never touch each other, but they all have the power to blow small startups out of the water if they appear to risk the bottom line.
That'd be very bad for innovation.
*) The patent system was never designed for ideas; it's a common misconception. That's why all software patents start with 'a method or apparatus to...' - they are patenting a hypothetical object or system that implements the idea. The upshot is simply that you are patenting the idea of course (in that any object that does what the idea embodies is a 'method or apparatus' and thus falls under the patent), but its kinda telling that the patent system has resorted to this 'hack' in the first place.