I think I asked a bit of a similar question to this when I first came to this board. After some time with the disussions and all, it's a bit hard to pin down one point that makes the MK-II and Hazel comparable on even footing:
- The Hazel was based on the GM Quel, while the MK-II was built off an original Movable Frame. IMHO, that makes the MK-II superior in terms of frame mobility.
- The Hazel has the advantage of it's systems being actually tested and proven in combat, which is why they were developed and kept, and why they were later put into the MK-II. But the MK-II development effectively stopped when the AEUG acquired them, while the Hazel (still in Titans hands), continued to be added on and tweaked until the end of the Gryps war.
- A lot of the development on the Hazel eventually went into the MK-II, but only at the point in time the MK-II project started; by the time the first prototype MK-IIs were flying, the Hazel would have already been improved further down the tech ladder.
- How much of the MK-II's performance can actually be attributed to Camille's NewType capabilities? I may be mistaken, but far as I know, none of the T3 team are NewTypes (or if they are, definitely nowhere near Camille's level). Having a NewType abnormally swings the scales in the MK-II's favor. Not knocking Emma's piloting skills, mind you, but you've seen Jerid flying the MK-II. If it hadn't been Camille piloting the MK-II, I doubt that it would have lasted beyond the Jaburo drop; the Messala, Gaplant, and Asshimar were already active at that point in time.
IMHO, the Hazel is superior to the MK-II for one main reason: Adaptibility. The Gundam MK-II has a Movable frame, but for all intents and purposes it's a very traditional MS design, and the only development to it throughout it's service with the AEUG has been the G-Defensor. It's a good MS in ground combat, but horrible everywhere else without a Flying Armor platform or the G-Defensor. And the G-Defensor has it's major limitations as well--it gives the MK-II extra power and speed in space, but requires another pilot to carry it into combat--and let's face it, the G-Defenser's core fighter pod is a sitting duck once the Super Gundam is put together.
The Hazel, on the other hand, has had a few years head start, the advantage of multiple systems developed to give it advantages in differing environments. Icarus flight unit for atmospheric flight, the Hrududu for space combat, Shield Boosters, armor, sub arm units, and most importantly the capability to work with other MS (Fiver, for one)