So people are getting their physical copies of "Pathfinder Unchained" and instead of being the
BIG BOOK OF D20 FIXES people thought that they were getting it is instead quite literally just a pathfinder version of unearthed arcana. Enworld has a detailed preview.
Basically, I would venture to guess that except for the stamina system and the class fixes that exactly NONE of the other changes are ever allowed in pathfinder society play. Which basically means that this will be a big book of shit nobody cares about because you can't ever find a game that uses these house rules adjustments to the 3.5 houserules that are pathfinder.
The only reason I think that the Stamina system will be allowed is because it is entirely contained within feats and PFS play really only limits people to not taking item creation feats.
Further, even the EN World reviewer seemed
underwhelmed by what the stamina could be used to do. You have to have an assload of feats to be able to do more than 1 or two things with stamina anyway, and then what you can do STILL does not appear to be as good as buffing with longer duration buffs and running through the dungeon.
The fact that they offer 4 different ways of fixing the skill system and most of them are completely incompatible with the others means they don't have a fucking clue why the system sucks.
The one thing I did find interesting was this
The next part is the removing Iterative Attacks system. It works like this: When you make a full attack, roll your highest bonus and then compare it to the target's AC. If you fail by less than 6, you do miss damage. You do damage on a hit, and land an additional hit for each 5 points of success. Criticals apply to one hit, and there are special rules for TWF, Natural Attacks, Haste, Rerolls, and True Strike that I won't explain here.
I actually think that this is a little bit interesting. A system like this would seem to help do two things. First it would make power attack and its ilk obsolete by virtue of making attack bonus more relevant.
Secondly it would seem to help with the issue of armor in D&D not feeling like it was worthwhile at high level. It might be purely psychological, but feeling like your armor protected you from a portion of the damage would help people feel like armor was not pointless.
However, I don't see how this sort of change could be implemented without a significant rebalance of every monster and PC in terms of hit points armor class and attack bonus. It seems like if you just drop this in an existing game your PCs will take more damage and die and you will be back to the old way after a session or two. Its hard to talk in detail without more specifics but this, like converting armor to damage reduction, seems like it wouldn't work without a huge amount of revising of material in order to incorporate it for what is a very slim gain.