I just ran through some encounters from a PFS scenario, and had four players play one playtest class each. The consensus is they all do fairly well compared to existing classes, and I tend to agree.
Things that stood out to me as a GM:
Investigator: Study can be pretty difficult since you’re using a Wis based spell (perception) as an Int-based class. Had Study just been a form of Recall Knowledge or making a Perception check using Int instead of Wis would be a smart way to go, in my opinion, as the investigator is just a bad fighter when unable to utilize his class abilities relatively consistently. This was particularly true when we fought a lv 6 creature with super high will saves, making the investigator completely give up trying to use their main combat ability on them because they needed to roll a 17 or better to succeed at the study alone. A few suggestions that could help fix that: 1) give investigators a feat that lets them auto study creatures they’ve already succeeded or crit succeeded on a study. So long as they spend the one action to study, they’d get the benefit of a success. 2) Allow Investigators to choose between Int or Wis as their class ability score. For that matter, add Cha there too, as that would really allow players to really customize how they want their investigator to act during their campaign. That way, Wis based Investigators will have a good chance to succeed at Study, 3) make Study key off of Int for the perception check rather than Wis. 4) just make it part of a Recall Knowledge check.
Swashbucklers: a bit of the same as investigators honestly. Both classes are really good against equal or lower level creatures but vs big bads, consistently able to gain some sort of class benefit could go a long way. Maybe spend an action to gain panache until the end of the round but can’t use that panache for a finisher and gain less bonus damage, but it requires a significantly easier DC or maybe even no DC.
Oracle: flame and life curses need to be rebooted. Battle oracles could use a small damage boost as part of their curse benefit. Mystery initial benefits for flame and life a bad and should be replaced with something more unique. I mean, the flame oracles benefit is about as good as Canny Acumen so we should really go a step above that. Toughness for life oracle, too.
Witch is actually in a decent spot IMO. Reach spell is absolutely needed for them, however, as it can be used to encourage witches to use their offensive hexes on creatures without putting them in serious harms way. Also every other spellcaster class has it.
All in all I’m happy with the classes. Some need some major tweaking though