Oozemorph Shifter. Not powerful by any means, but an amazing concept. I love that playing an ooze is now an option in 1st party pathfinder.
Some new water descriptor damage spells. This is mostly because I really like my waves shaman with crashing waves, and now there are more water spells to leverage.
Brawler archetypes. So much cool stuff there. Especially living avalanche and venomfist.
Meld with familiar is nice for me, because I don't use my familiars much but really like keeping them safe.
New familiars. The more the merrier I say, and I especially like core penguin familiars as opposed to being in a bestiary or a splatbook.
Giant Mantis Shrimp Bodyguard animal companions. I really want a GM to okay a wild child brawler who learned boxing from his bodyguard shrimp. Shrimp takes bodyguard/in harms way, brawler takes beastmaster style (another nice addition), they push and pull eachother out of the fray constantly. Just need an aquatic campaign. Or a GM willing to let me ignore that aquatic subtype.