Zardnaar
Legend
You're not just comparing feat to "no feat" though. You're comparing IMO the one truly overpowered feat (I don't consider GWM overpowered btw) AND another feat it pairs extremely well with AND a maneuver that goes perfectly with it - to no feat. That's a lot. It's certainly not a reason to ban feats in general (as a different poster suggested).
To which - ok it's potent IF you consider DPR top priority. My group's fighter went the defense route (protection style, sentinel) and hasn't been the least bit disappointed.
If you kill everything that much faster defense doesn't matter as much. Death is the best debuff in D&D.
But yeah Frogreavers combo is very broken I've seen it in actual play.
I called these feats out roughly 6 years ago. Opinion in them hasn't changed.