Feats were never publicly playtested as finally written, if my old packets are complete. GWM let you auto-crit for -5 to hit. Sharpshooter (under a different name) gave you an extra attack but all attacks that round were at -5. Yes, both of those are awful designs, but that's kind of the point. They didn't even have sound math. The final designs really bounced around. I also recall that between the last playtest and the final version, Ogre got +30 hit points and -2 CR.
The vast majority of spells were either not in the playtest, or never changed, or only changed after the playtested concluded. Especially spell levels 7+, which is basically what has made the last two tiers of play so commonly frustrating and difficult to run that WotC barely acknowledges it's existence anymore. I only recall Mud Sorcerer's Tomb as the high level adventure, and I remember my friends playing it fairly early in the playtest before most high level spells were available. I really don't see how they could get playtest feedback on high level spells with that.