@Rich.h. Modern militaries commonly employ major designs, which go through modifications over its service life, and eventually are supplanted by a future, vastly different design. This suggestion is natural extension of Aurora upgrade system that tries to take that in to account. Our upgrade system include three elements:
- The first are the "basic/core" components which has no upgrades or will upgrade immediately when the background tech is researched, with no cost, and no requirement to go to port. I imagine those as things can be handled by the crew like software updates or things made available with basic maintenance supplies. (unchanged)
- The second are "design" components these need to be designed, prototyped and installed when the ship is in port. Limited internal system upgrades can affected in the original slipway, cost considerably less than building a new ship, but take more time. I imagine those as modular compartments replacement install a higher res radar, outfit a turret, etc (unchanged)
- The last is hull armor retrofit which is a fundamental change to the ship structure, not a paint job. These should be a substantial undertaking that cost resources based on the size of the project.(changed)
Right now with miniaturization, ever expanding shipyard capacity, and no diminishing returns to building bigger (Which I suspect that NPR generation don't take into account) its a system with only upsides that doesn't encourage verity. Also you can keep retrofitting the same ship from "wood" to super duper technobuble tech over the course of centuries.
This suggestion offer the same, but offer more options by making smaller ship more economically viable long term. Its realistic, its great from RP stand point (older capitals with newer escorts), and most of all for you its non-intrusive i.e. Since hull armor retrofit aren't that common, this sort of ship upgrade system would have a single design live for quite a long time; Unlike overhauls, it requires no endless micromanagement; and it offers no hard limits, only little thinking and planing. So your emperor can still build his megalomaniac projects and upgrade, at a cost.
p.s. Sorry had no time to read all the post since, or make more than this quick reply. Hopefully I didn't miss anything.
Edited.
Btw, people please don't forget its not about the economical constraints of big fleets, but whether a person with the same industrial capacity is better investing resources in either building 400kt shipyards\ships or twice as many 200kt shipyards\ships, for example.