Probably won't happen for the same reason they don't make Grapples or Throws. What happens when my 8 ft Inv/SS Tanker head butts a 3ft Clockwork? What happens when my 4ft MA Scrapper head buts a Cimeroran?
There are certain kinds of strikes and moves that can't work because there's no hit location system in this game to control how animations end up looking.
"Null is as much an argument "for removing the cottage rule" as the moon being round is for buying tennis shoes." -Memphis Bill
By that standard, many punches and kicks should not be in the animation suite. But perhaps you are correct that my calling it a headbutt is too precise--similar to calling something "a kick to the shins" as opposed to just a kick. My suggestion/request is for a couple attacks where the attacker uses his/her/huge's head to attack their target--regardless of whether they hit head, chest or shin.
If you're not concerned about whether it looks like it's "hitting" the target, that's fine - but consider this:
It'll be too subtle of a motion, to work with. Remember that they don't use any motion capture in this game's animation, anywhere. The animations we have are all reasonably obvious. The character would really have to lean WAY back and propel themselves WAY hard forward, to make it look like it's a hit at all. A quick bashing motion (like, what you'd actually do if you were in proximity to someone else's head) would be more easily animated as "/e nod" and isn't particularly impressive.
I'd rather have an entirely new set of melee (staff/scythe/etc) than just replacing or adding one headbutt into one or two powersets. Still, it'd be fun, I'm not saying it wouldn't be, but between the lack of dynamic animation potential and the fact that we really don't get anywhere near the enemies to 'hit' them, I don't see it happening any time soon.
Please read my FEAR/Portal/HalfLife Fan Fiction!
Repurposed
I was obsessing about this on the train to work today... because that's what one does in this town.
With power customization, I would LOVE LOVE LOVE to see a few alternate head butt animations added to both SS and MA. For MA, a quick snap of the neck make-those-hooligans proud sort of head butt and for SS a couple animations that could double as head rams or rhino/bull goring animations.
BABs, if you are so kind to grant these to us, I promise to use them responsibly. I swear.
(And I'm starting a thread about this because I've yet to see a proper official stickied "put all PC suggestions HERE -->" sort of thread...)