All good points but what about fire coverage on Special Attackers?
If you're trying to wall special attackers/set up against strong special attackers with Mega-Scizor, you're using it wrong. Mega-Scizor's greatest utility lies in it's great physical bulk; unless it's confronting something which it knows it can wall on the special side (like a defog/roost/psyshock/draco meteor Latios) it shouldn't be matched up against special attackers. M-Scizor's use lies in it's ability to discourage those special threats from switching into it, and, when it can't do that, escape with U-Turn (or, if it can, proceed to boost on the switch and beat these sweepers). Mega-Scizor shouldn't be taking hidden power fires; it shouldn't be your answer to specially offensive pokemon in general.