For less than 1 round, using a limited resource? Not really, at least IMO. It's easy enough to get advantage on attacks against other creatures.
All well and good - I just wonder whether you really need two abilities that allow pushing, when you could have one and the players can reflavour it to suit (Alice the monk does a kick while Bob the fighter does a power shove, for instance, but they both use the "Shoving Attack" ability.)
What makes this overtuned, I think, is that most of these manoeuvres let you make a weapon attack, add the manoeuvre die to the damage, and often achieve some other effect as well - but against a single target. This manoeuvre lets you make a weapon attack and achieve some other effect against multiple targets. Perhaps the way to go is to make it an AoE shove without the attack.
Well, leaving aside variant human, the earliest you'll get this feat is at 4th level, one level ahead of monks getting Stunning Strike. Once monks get Stunning Strike, they can use it up to five times in between short and long rests, and the number of times they can use it increases as they gain levels. By contrast, you can use the head shot up to three times between short and long rests, and unless you take this feat multiple times (which is usually not going to happen), you won't be able to use it more often. And for both you and monks, there is an opportunity cost to using your resources on this attempt, since you won't have the ki or manoeuvre die to use on another ability.
But if you still think it's too much, you could have head and body have the same effect - extra damage on a failed save.
Fair enough.
You're welcome!