Uh, dammit... because the obvious answer was that it would have locked slots which could take a refinery and nothing else but a refinery.
Perhaps the answer isn't to nerf mining to where it doesn't compete but buff trading to where it does?
Trade ships need two things: big cargo holds and big defenses (not offenses). Better turret placement hardpoints, larger module slots for cargo and shields, fighter bays in not just the Type-9 and Cutter, and large enough distributors and power plants to handle these needs. The tradeoff is low speed, middling FSD range (multi-roles suit the long-distance rare trader far better, and this makes sense anyways) and lack of hardpoint utility for anything BUT turrets.
Mining Ships need two things also: cargo holds and slots for equipment. Hardpoints better suited for mining, internals that are of smaller size but more numerous for the myriad equipment and holds, better agility for navigating asteroids and a stronger FSD for traveling as you search for 'that perfect spot'. The tradeoff is low defenses (bring a friend or mine quickly) that rely on 'flight' instead of 'fight', and ample cargo but not comparable to a trade ship (your cargo is worth more per ton after all).
So let's use two existing examples and how they could be modified: the Keelback and the Asp Explorer, a trader and a miner.
- The Keelback can have robust defenses with larger slots and a SLF and properly placed hardpoints for turrets. The slots are few, but greater in size to increase cargo at the expense of variety of modules. FSD is middling to allow normal transportation across nearby systems, but you don't want to trade rares in it.
- The Asp Explorer has many hardpoints and slots, but of smaller sizes and more forward-oriented to make mining easier and intuitive, while also have strong engines for agility and a solid FSD for traveling to new sites or returning with your most recent find. It's smaller slots limit shield strength and total cargo capacity compared to the Keelback, but it'd make a strong deep-space miner or a quick in-n-out ship for high-risk mining sites.
Just my two cents on ship design...I agree, locked slots are pointless and not needed as many other ship stats can be augmented directly (Hull, Mass, Internals Size, Ship Size, Agility, etc.) to create 'classes' of ships without totally restricting the commander. I explore in my Corvette, for example, fully fitted for combat - it only has 30ly range but I love flying the thing. That doesn't make it superior to an Anaconda, but I'm not 'forced' to use an Anaconda to get the same thrill of a large ship fully outfitted with 4 SRVs and SLFs to play with in the black! Ship Design should follow these sorts of guidelines to provide choices without creating either extreme of 'Any Ship Can Do Anything' and 'Only This Ship Can Do This'.
