The bigger ones I can remember:
FFXIII announced as multi-platform (also on 360), by SE
Resident Evil 4, Resident Evil 0 and a remake of Resident Evil, as well as the Capcom 5, exclusive on Nintendo GameCube. Eventually, Resident Evil 4 made its way to PS2, and there was a small flare up with fans and a bigger flare up, causing Shinji Mikami to quit Capcom.
Silicon Knights and Factor 5 abandoning Nintendo
Bioware and DICE being gobbled by EA
Monster Hunter (and Resident Evil handheld) shifting toward 3DS and Wii(U), away from Playstation brand
Bayonetta 2 appearing exclusive on WiiU
Nintendo selling RARE, MS acquisition of RARE
Epic developing on iOS (Infinity Blade was originally a Kinect game idea)
Bungie leaving MS
- some minor things:
3DS 250$ pricing and value vs Vita, 3DS screen scratches, Lost Odyssey and other JRPG's only on 360, Vita flopping everywhere, iOS/Android vs portable gaming....
Lots of things.