[quote=@Kimiyosis]
Curious, what if you are designing a support type FRAME?
I'm talking long range missiles and Multiple different ECM as well as an Imaging Suite.

Would you still need an auto cannon?
[/quote]

The guideline still stands; it's the primary armament of all military FRAMEs. That said, you could have cannons of varying calibers and rates of fire, which would make slight changes to how the weapon is used in combat.