But...
Why should a behemoth such as the PC be nerfed from day 1?
Why not have 4 off C8 Thrusters
4 off C8 shield generator slots with 12 - 20 Utility mounts
2 -4 C8 PP / Distro
More hardpoints than a stick can be shaken at?
Ridiculously overpowered ships have
less soul, not more! I've flown them inadvertently in mods of other space games and they're just incredibly meh. Grabbing this insane power budget for themselves doesn't make them feel cool longer than about five minutes, and it also destroys the experience of the entire rest of the ship roster by rendering them unviable.
I think the biggest risk to the ship's "soul" isn't that they give it 20 utility mounts or multiples of core internal types (which they absolutely won't do), it's that they make it a fleet carrier's oversized cargo shuttle – a ship you absolutely never want to make a single jump in, whose only purpose is being a coloniser's ferry.
Going to Stealthie's question about how it should be limited: cargo. Yeah it should have the largest cargo capacity, but not by so much that it's unbalanced to give it some big guns (designed for turrets) and isn't a ship you can enjoy flying. This ship is meant to be the end goal of any trader, their pride and joy.
Re: internal balancing, only shield cell banks and the generator itself make good use of internal sizes above 5, so just focus on sizes 6-8 to mitigate too much stacking toughness (but it should be tough). More important thing is its firepower should be heavily designed for turrets. It can be indestructible, but shouldn't do well with meta weapons.