I counter your observation with the notion that we're weilding matter, space and time using technomagic. With that in mind why can't i do something which annihilates a thing behind me? I'm not pointing a gun or swinging a sword; i'm manupulating a nanobot cloud and energy fields.
NT i'd say is as it stands a pretty unique form of combat in AO where we are unlinked from the regular weapon system and therefore quite rapidly omni-directional in our attacks. Which is good for casters considering how we divert our attention for calms/roots/blinds etc - if we altered angle for casting for example we'd end up just spinning on the spot in a decent fight
I still feel we'd lose a bit of the NT uniqueness and freedom from having a regular weapon managing our character-facing direction in combat.