I really like the blue line mechanic on the Huge ships, but we ran into a scenario last game that I had a question on.
A TIE had maneuvered to the side and just behind the GR-75 such that the fore section was obstructed by the rear section but only the fore section was in the TIE's firing arc. Since the center-to-center crossed the blue line, it was obstructed by the rear section, but the rear section wasn't a legal target.
At the time we ruled the shot was ok, since it seemed to me that the intent of the rule was to force fore/aft targeting on the ship, not eliminate it from being a target. We also talked about maybe giving an extra evade die to represent the extreme angle shot.
I'd be interested to see if others have run into this and what they picked and if any other Huge ship issues have come up.