I'm actually fine with Golarion - I haven't yet begun to plumb the depths of all the stuff that's available just in the little corner of that world that is Avistan. I'd love to be involved with something run in Kaer Maga - that city calls to something in me, and there are so many plot hooks and so much room for adventures there . . .
I think the Mythic rules are pretty cool, but not for everyone. It's good, I think, that they're there for those who want to use them. I see them sort of like the alternative armor systems, the alternative magic systems, and alternative alignment systems that have been put out in various rules books. They're different enough that it's very clear that they are alternate systems. They're not - generally - meant to be mixed with the core systems already in place.
I'd love for Paizo to stick primarily with the stuff on which they built their reputation - stories and adventures. But so far, at least, they're doing a good job IMO of putting out quality rules supplements as well. Take that with a grain of salt, though - I jumped on the Pathfinder bandwagon when they rolled it out primarily because I was heartily sick and tired of the rules bloat of 3.5. It got to where a poor soul like myself, who didn't have the time or the inclination to keep up with the third party stuff that came out every other day, could hardly play a character that was useful to a party 'cause all the other guys had the coolest new toys and the time to figure out how to make a character to take advantage of every loophole in the rules.