I just got a notice from Amazon that they are sending out my Pathfinder playtest book and I'll get it right on time on the 2nd of August. My excitement continues to grow.
I've been very interested in the hints about how they want to do multiclassing. Treating it more like a very involved archetype rather than trying to just alternate classes. A recent blog post gave me a taste, but I really want to dig in and figure out how it all will work. I think it'll let players really tackle a character concept they have in their head, without completely derailing their relative strength level. That was one of the problems with 1st Edition multiclassing that was inherited from 3rd edition DnD as it was easy to make a drastically sub-optimal character if you multi-classed the wrong way while munchkins could abuse the system with some very particular selections. I also think it will help the problem the Unchained Rogue had. They had to hide dex to damage until 3rd level because otherwise it was a far to powerful dip to give at first level. This ultimately penalized rogues because they had to be quite nerfed until they could hit third level and realize their full character concept.
I'll post more when I get to have the book in my hands with some time to digest things.