That depends. Are there a lot of Pathfinder fans participating in the playtest? Because that is a major part of the target audience.
We're at the point where most of the mechanics are locked in (or being locked in), and what is left is generating a couple hundred spells/maneuvers/powers/monsters/feats. Because that's the part that takes time; writing a basic resolution framework can be done in a few days by any competent designer.
That means that, for example, if you don't like expertise dice or vancian casting, well tough luck: they're here to stay, that ship has sailed.