Please can the classes have a table for the "Adolescence and Training" section of the background generator in Ultimate Campaign in the final book. I know it's a long way off and not something likely to be even on the radar just now but just registering my interest in them having it. It will make them feel more like 'real' classes to me if they get the same full treatment as other base classes.
Thirded, and taking another step further ...
Expand on some of the existing backgrounds, like the Oracle. That one especially seeing as they had at least 14 mysteries before publishing Ultimate Campaign, yet only used 10 options. Some GMs would tell you that what you rolled was your actual Mystery, and there was very little wiggle room to negotiate a different one unless an archetype was involved or some overlap in the mysteries. It gets worse after the additional ones in other books.
Expanding on existing character backgrounds can allow for use to personalize the story a little more, and give players a better chance when dealing with strict GMs who only let you use what you roll as trait options. It lets us express a little more on the Rogue who trained as a swordsman, the Druid raised by billy goats, or even the Sorcerer who discovered her talent in the middle of an embarrassing episode involving two bushels of grapes, a trout, and a wheelbarrow.