I think the Minotaur should be considered around what guns will counter it and what guns counter it.
Presently, I agree that it does way too much damage for a weapon that so severely impacts mobility at such long ranges in a game where mobility is seriously a huge, screaming deal.
At its present stats of .44 shots per second, 9-sec reload, 4 clip size, 60 direct piercing, 175 burst shatter, it presently ranks 9th (out of 17) in armor damage and 6th in component damage (DPS, including reload times). This all doesn't seem so bad, until you also consider that outranges the hell out of everything EXCEPT the Mercury, while at the same time hitting almost instantly, especially with the pinpoint accuracy granted by heavy clip.
While I think its range definitely sorely needs a reduction, I would imagine reducing it to merely 800 would suffice; this would mean it would be outranged by the Artemis and the Manticore in addition to the Mercury. This would allow both weapons to counter it by destroying it before it becomes too much of a nuisance. At the same time, the Minotaur would still be very much useable as a counter to both types of Carronades by knocking approaching ships off-course.
To be honest, I think balancing the Minotaur should not happen all at once. Making a single change and then observing its effects on the game would give insight on what else (if anything) needs to be changed.