To be fair, its actual performance is better than people are giving it credit for.
It has a fair bit of regular kinetic energy dump, seeing as how it visibly pushes the female MUTO around, even briefly reversing her momentum. Its heat is also immense, being able to damage her where nukes are considered iffy.
And of course you have the moment where it burns through her neck cleanly. Upon further analysis, it's actually quite a strong iteration of the atomic breath. It just looks more realistic, being a plasmatic vapour, and thus not as visually striking as a solid beam. I do agree that it has a more refined appearance in the upcoming film.