The Phalanx isn't a heavy assault unit; it's counterpart, the Nataku, is.
Regardless, a high-performance melee combat power armor seems like a waste of resources, especially if you plan on mass-producing it. Melee weapons, by and large, will get the user killed if facing anyone with sufficiently powerful ranged weapons because by the description, it's not very heavily armored or shielded.
If anything, this is a specialist's armor simply because of what you want it to do.
In truth, I don't think this unit would be necessarily, especially since it's not capable of anything the current generation of power armors isn't.