dev blog for Pathfinder Online, CEO Ryan Dancey announced that the game is half done, stating,"We're a little bit past the halfway point of development before Early Enrollment." Luckily for those eager to hear specifics about said progress, the blog goes into more detail -- a lot of details! These details, provided by Designer Stephen Cheney, focuses on changes to the spellcasting system.
After bumping into difficulties with the system as first proposed, devs came up with some solutions to address concerns. The new system includes a new class of weapon that produces expendable effects (called spells for casters and maneuvers for non-casters) and alterations to the Refresh system. The expendables are also dropped as loot and treated like learned feats, which also prompted a few changes in active feats. You can read up on all the details in the blog post.
[Thanks to Crysillis for the tip]