The SD folks continual scheming to get Miramar is very amusing, and apparently never-ending. It usually goes something like this:
SD: See, Miramar would be perfect for a new airport because-
Marines: No.
SD: -growth at Lindbergh is impossible, and Miramar is more remote but still has freeway-
Marines: No! Negative!
SD: -access, and we could still use Lindberg as a commuter field-
Marines: N-O spells "FUCK NO!" you clowns!
Anyway, Navy/MC in general doesn't like the idea of sharing a field with civvie traffic. The AF does it a lot, and makes it work, but every time I've seen it, it's been sharing with small regional airports (Eglin, Charleston), not a major metro hub like San Diego.