They're slayers.

You're obscuring the argument by making an incorrect and flawed example with the assault dropship. The 'Assault' part of the assault dropship is what makes it able to combat other things - this is what defines it as the 'slayer' dropship. The 'dropship' part is what makes it a 'customizable' role. In fact the 'assault' dropship is less customizable than its non assault counterparts, it has less fitting and it's only real tradeoffs are nose mounted guns, improved weapon performance, quicker turnarounds and increased speed/maneuverability.

Thus if we take the regular frames and apply the same logic, assaults 'should be' 1) faster, 2) have increased weapon performance, 3) have faster turnarounds, 4) less customizable, 5) less oriented towards equipment, 6) far more oriented towards slaying.

Your 'argument' is wrong, has been explained why and where its wrong and is thus dismissed.