Using "slot size" has some pros, but also more cons, especially implementation-wise. It is a lot more awkward to have different sized icons jumbled together in the "ship parts" panel. There is no ideal solution that doesn't result in odd, space-wasting gaps.
If that's such a big deal - and I'm not sure that it is; we could change the layout completely to something designed to support different sized ship parts - we could use some other visual indicator to show that it's a large part. For instance, it could have a black background instead of grey, and then when you begin to drag it out of the parts window, it would expand to its full size. Or, if you don't like that, there are doubtless several other possibilities. Since we have total freedom to design the UI, I'm dubious about any argument that prefers one gameplay feature over another based on our current UI.
Secondly, and more importantly, it's not really practical gameplay-wise. Would you have any ship that can hold a colony pod be capable of mounting a Stellar Converter?
Why not? The only early hull with a "special" slot might be slow with very low structure, and have no other slots. Yeah, you could put a stellar converter in it, but it would be very vulnerable. On the other hand, by the time you have high level techs like the stellar c. you probably also have a better hull with a special slot.
Because by having a Stellar Converter and a Colony Pod use the same type of slot, you're committing to having exactly the same restrictions on what type of ship can carry them. Sure, in the beginning of the game, the only ship with a special slot would be slow and weak. How about later on, though? I can't imagine that we would prevent the player from building fast colony ships, but having a fast planet-destroying death star just seems like the sort of thing that shouldn't be allowed, for reasons of balancing, and because it's just plain goofy. Gigantic epic weapons should feel
gigantic and epic. If I can put one on the same hull that my first colony ship was made from, it feels a lot less gigantic and epic.
In addition to the question "Why not?" I ask: How would using "large" slots instead of "special" slots make any difference in regard to that? You could still fit a stellar converter in the same "large" slot as a colony pod, unless you plan to use more different slot "sizes" that just "standard" and "large". And I don't think that's a good idea, I wouldn't go down that road. If we implement something like this, the UI will quickly become complicated and cumbersome to use.
We wouldn't use large slots for colony pods - eleazar was just suggesting that the special slot could replace large slots, in addition to solving the problem at hand. My suggestion for dealing with the problem at hand was to remove the internal slot from the small hull and give it more fuel, which we did. Now the issue is the larger question of whether it's better in general to have large slots, or a special slot.