I thought about it further and more carefully, and it became clear to me that the only thing that would get me to use the Pathfinder RPG rules to run an adventure path that runs to the mid- to high levels is if Pathfinder RPG fixes the one thing that I had grown to hate about 3.5 as a DM: buffs.
I need Pathfinder RPG to fix the fact that in 3.5 high level games, keeping track of buffs becomes an accounting chore, and that a buffed party is way more powerful than a non-buffed party.
Of course, fixing that then may require rebalancing the CR system to know what monsters and what NPCs truly are at the same level of power as the party.
If Pathfinder RPG can fix that fundamental problem I have with 3.5 Edition D&D, then I would consider running another adventure path with those rules. Otherwise I'm bailing and going to 4th Edition, and hoping that some day Paizo will join me over in 4th Edition so I can once again use their great adventures out of the box.
I think Paizo is a great collection of talent and passion for the game. So I wish them success. But nothing would please me more than having Paizo by 2009 start putting out Paizo 4th edition adventures and to have WOTC hand back Dragon and Dungeon to Paizo so Paizo can support 4th edition through the magazines in the same way they supported 3.0 and 3.5.
See, I was really hoping that WOTC's GSL would permit Paizo to give us back a Greyhawk-like world but using 4th edition adventures. I liked the old school D&D world, with demons and devils in their old roles. I liked old-style elemental planes. I liked gnomes. But I was tired of the 3.5 rules' complexity for DMing high level adventures. I would have trusted Paizo over any other company to do "4th edition rules, 3.5 edition feel". But I will certainly be looking to Necromancer Games with much hope in my heart, and I plan to support their efforts hoping they succeed in bringing this to pass after all.