I've been trying to dig up a page to link to (that isn't "World of Tanks" related) that would emphasize tank design and have numbers for cannon depression. While I haven't found an 'official' page there is lots of info corresponding to the less than 10 degree declination and numbers of 20-30 degrees inclination.

The design comes from a few factors:

- placement of crew inside
- mechanism for firing cannon
- amount of armour, and placement of armour on the tank
- weight and balance of the tank

I think a few of these items might have been overlooked by CCP in the design of our HAV's or they are slightly skewed. I do believe you're right that the Madrugar can aim lower, despite it and the Gunnlogi having similar silhouettes. Even if we assume that the large Blaster doesn't require a firing mechanism in the turret (like a "Metal Storm" weapon) and thus can offer a greater range of motion I still find it dubious that the engineers would design it in such a way.

Both of the current HAV's offer the option of 2 additional small turrets. Both of these would be far greater suited for precision strikes on nearby infantry, and how often do we see them being utilized? The depression on the cannon coupled with the accuracy of the Blaster has been exploited by tankers who found it was more satisfying and more convenient for them to run as solo machines.

I'm hoping that in future builds with either armour/shield alterations to HAV's or a more effective AV arsenal that infantry will be able to become a real threat to HAV's.