The problem with this theoretical discussion is that we're comparing a mish-mash of versions of a game that didn't exactly have a firm foundation upon which to build it's tech bible upon to begin with. And it's also not a wargame, it's an RPG that got this stuff tacked on to it.
As to Theophilus comment about VTOL aircraft on assault ships, the USN originally discarded the smaller carrier concept after the 50s in pursuit of the larger carrier to handle bigger and heavier jets. Other navies have maintained the idea of smaller carriers, mostly because they can't afford the budget required for a full-sized carrier. We've seen a mix of smaller and less capable VTOL jets to smaller jets with less payloads using ski-jumps and the ships carrying fewer (think Chinese and French).
At the end of the day it's probably boiling down to more of a budgetary question than a force projection/mission question. No other nation has the same mission needs that the USN has for global force projection. And no other nation has the budget that the USN has either. Were this a pure space question I'd think you would see planetary navies using smaller carriers as well, and just the Imperium deploying larger fleet carriers.
As to Theophilus comment about VTOL aircraft on assault ships, the USN originally discarded the smaller carrier concept after the 50s in pursuit of the larger carrier to handle bigger and heavier jets. Other navies have maintained the idea of smaller carriers, mostly because they can't afford the budget required for a full-sized carrier. We've seen a mix of smaller and less capable VTOL jets to smaller jets with less payloads using ski-jumps and the ships carrying fewer (think Chinese and French).
At the end of the day it's probably boiling down to more of a budgetary question than a force projection/mission question. No other nation has the same mission needs that the USN has for global force projection. And no other nation has the budget that the USN has either. Were this a pure space question I'd think you would see planetary navies using smaller carriers as well, and just the Imperium deploying larger fleet carriers.