Quote:
Apocalypse Missile Launcher - 60cm 3BP, if all a titan's weapon choices are Apocalypse Missile Launchers they have indirect fire.
That's a special rule regardless of where it's placed because it's conditional to a specific situation. Single Apoc launchers don't gain indirect as part of the weapon nor do two of them. It only happens if that's the only weapon you take.
If we entertain the notion of going this route, we devalue the already free CLP by making it unnecessary for the lower cost artillery titan. A chance like what you propose isn't good for the list. The configuration with all Apoc launchers is a functional and valid configuration as it stands although not optimal.
If we really wanted to mess with it, we could think about disrupt. It is after all saturating an area with missiles. It would also create three kinds of uses for differing weapons systems on the titans.
Inferno Cannon: Extremely cheap indirect fire titan that ignores cover
Apoc Launcher: cheap, but decently long ranged indirect fire titan that causes disrupt
Quake Cannon: Expensive, extremely long ranged indirect fire with MW
I would be hesitant of the effect on direct fire titans and the standard load out titans, but they could use a small boost to be more attractive.