E3 is still around, it will just be limited to press conferences and invitations will be very low: only 5000 acre expected to attend the actual show.
I expect GDC to replace E3, especially since they expect next years to be roughly four times larger than this years, which would make it similar in size to E3.It would be great, though, if we had multiple shows. Still, I do think the pre-E3 press conferences will be where most of the major news is presented.
I'm sort of hoping for nothing to appear as the new E3. E3 was by most accounts a clusterfuck. I think more specifically targeted, smaller shows (GDC, PAX, BlizzCon, etc.) are for the best.
E3 needed to go. It was crippling the industry for months at a time.
The grand party at the expense of the industry was fun, and wild, and thrilling, but I'm not surprised that people finally realized it was sucking up a lot of money and not really giving anything in return.
PAX will pick up the "gamer-party" aspects (I'm guessing), GDC will pick up the indie dev energy, and the "new E3" will retain the supermoneyed publishers and big-name devs. I have to say I'm pretty skeptical of the GamePro Expo thing, myself - sounds like a highly corporate attempt to pick up what there are already a ton of other (and possibly better) conventions trying to do...