Accuracy is your chance to hit with any attack -- weapon, spell, gun, etc. doing damage, causing status effects, etc. -- it doesn't matter. All other things being equal, 1 point of Accuracy is 1% greater chance to hit (shifting crit, graze, and miss accordingly). When you do something offensively, you are always trying to hit and that always depends on your Accuracy vs. the target's defense(s).
Penetration is armor negation and it's something I'm less interested in attaching to Perception than Interrupt. If we did use Penetration as something modified by Perception, every attack that does damage would have a base Penetration that could be increased by Perception. It is more likely that we will stick to the old system, in which some specific spells and weapons have an inherent Penetration but other attacks simply try to brute force through DT the old-fashioned way (more damage).
As a side note, we're extremely unlikely to have attribute prereqs for Talents. In the last Pathfinder game I ran, I removed ability score prereqs from every feat and it make no discernible difference to the balance of the game (of course, I also made all of the ability scores more equally valuable, which helped).