Look at modern merchant shipping. I can name half a dozen different types of cargo ships offhand, and that's not even looking at military ships. Special roles are a fact of life. If anything, Aurora is probably overly generous in this regard.
Sure let's look at modern merchant shipping! 90% of all global shipping tonnage (excluding fuel which is also a separate thing in aurora and should/will stay so) is done in standardized containers which can contain almost everything of value and be carried by almost all cargo ships and unloaded in all larger ports. Most specialized ships are small coastal ships and not between main hubs ( meaning their equivalent ships would be below the scale of Aurora 4x ).
Similar with military cargo ships, there are 3 main types in use in the US Navy. Vehicles Cargo Ships (AKR), Dry Cargo (AK) and Ammo (AE), but in practice the last ship have been obsoleted and replaced by AKE which can handle both Dry Cargo + Ammo and are "equipped to transfer cargo such as ammunition, food, limited quantities of fuel, repair parts, ship store items, and expandable supplies.". Over half of the military Dry Cargo (AK) ships both have RO/RO (roll on/roll of) capability and container capability so they can take some vehicles, containers and custom sized cargo unloaded by own cranes.
( source:
https://www.navysite.de/ake/index.html )
And there is little reason to not believe the development towards more standardization ( both in the military and civilian sectors ) would continue to develop further in a future sci-fi civilization.
Sticking troops on airlifters only works because they aren't there for that long. Keeping them happy over days/weeks takes a lot more specialized infrastructure.
Agreed with troops needing quarters for longer transits, but all their gear and equipment still can go in pretty much any cargo hold. A cargo ship with enough spare births should be capable of taking them just fine or you could ship the men separately from the equipment using any civilian transport ( as is/was often done IRL ).
Not saying Aurora necessarily must go to this level of detail/micro, but it's a good point about flexibility of cargo.
As for vehicles, yes, it is possible to stack them in a bulk cargo hold, but that's only a good idea when you're shipping them to a friendly port. If you want to unload them quickly, you need specialized equipment.
I never said that contested drops should be possible with bulk cargo. My entire argument was about cargo/vehicles unloading in friendly ports not needing 10 different types of specialized cargo holds.