The spear already does finisher level damage; it's below the Jackhammer by like 4 points, there's really no need to bump it
And it's only "Goldberg-esque," it's not meant to closely resemble any one spear he ever actually did

Amazing!!! Personally, I think you should either up the damage just by a couple of notches or make a new variant with the damage upped. Goldberg's spear, in my humble ass kissing opinion, should be rated higher than a normal Spear I think just because of how legendary he made it. One other thing, it looks really great, but I think he kind of holds on/carrys hm too long. You know the one he did to Christian in '03, right? He hit him and he goes down immediately, but Goldberg hits so hard it almost looks like he DDT's himself.

I hope I've given you some kind of inspiration