I'm kinda surprised that some guys like alt fire of Stingray. IMO it really lacks creativity and simply duplicates Falcon without zoom with even less damage. Laser beam was already mentioned, but it's an obvious replacement which simply copies from UT series.
I'd suggest just adding reflection from surfaces to alt fire of Stingray. In this case, Stingray would be totally different from Falcon and have much more utility than it has now. Just imagine someone crouching in ventilation on Foundation and awaiting for Mega Armor while getting all reflected fire in his face...