It's not exactly a GM's Day thing, but I'd like to see Rogue Genius Games revisit the Genius Guide to (Arcane/Archer/Divine/Martial) Archetype books once the ACG comes out, to support the Antipaladin, Arcanist, Bloodrager, Brawler, Daredevil, Death Knight, Enforcer, Gunslinger, Hellion, Hunter, Investigator (Paizo's), Investigator (RGG's), Luminary, Magus, Mosaic Mage, Ninja, Riven Mage, Samurai, Sensitive, Shaman, Skald, Slayer, Swashbuckler, Talented Barbarian, Talented Cavalier, Talented Fighter, Talented Monk, Talented Rogue, Time Warden, Tough, and Warpriest. Also, whoops, looks like you might need to rename the Investigator soon. ;)
You could probably release it as something like the Spellpoint Compilation, and I'd buy it right away, at least.
As a GMing thing, let me second the "Talented Bestiary". My biggest wish for it would be something like how the EverQuest RPG's bestiaries handled most monsters with character classes, by assuming the default was basically a fighter and swapping in some other abilities to quickly make a Fire Giant with Magus-like or Antipaladin-like abilities.
EDIT: Paragraph order helps.