I hope this request is already in there somewhere, but:
Please rework treasure generation and placement. The current CRB+GMG system is kludgey to the point of unusable. Percentage tables take up an incredible amount of space in the Core Rulebook and GMG, and yet I have never successfully generated treasure in a way that was easy or satisfying.
If the designers would have us pick treasure and place it in a semi-random way, let the rules call that out.
Include slots for "Reroll or roll from a book of the GM's choice" or some other way we can expand this table to subsequent books.
Include treasure hoard "templates" instead of 100% random — just a list of all the item types you ought to include, and a quick roll to randomize that (double potions, no scrolls, etc). Then some guidelines on places to stash treasure in the adventure (how much NPC gear? How much hidden cache? How much in monster bellies?)
Do everything you can to eliminate the frustrating process of generating invalid results and going back to the beginning.
Make sure these results work correctly with things like the settlement statblocks — I ran into problems with that the last time I tried the CRB+GMG method. I can't remember the specifics, I banished them with self-inflicted head trauma.
I do understand that these are legacy issues that stretch back even beyond 3.0... but it would be a shame to have this book released and miss the opportunity to fix it. Think of the effort you'll save on behalf of all those GMs! They'll run more games, which means more people will play, which means more sales! It's totally worth it!
(I apologize for my inappropriately strong feelings on this issue)