One thing I've noticed in Galciv 2 that simply shouldn't be true is that it is far more expensive to upgrade an old ship to a new design than it is to simply build an entirely new ship.
Once you start to swap out weapons and engines on ships of any significant size (small, medium, and up), it costs thousands of BC PER SHIP! Towards the end of the game, it would have cost me 180,000 BC to upgrade 20 huge hull ships. The only change was substituting doom rays for the disruptor III.
I understand that there is a formula that determines the cost of an upgrade to an existing ship, but this formula seems a bit off. When the cost of the upgrade is several times the cost of the ship itself, don't you think something isn't working correctly?
As it is now, I usually just demolish older ships and build entirely new hulls. Not only is that not "realistic" (in addition to not making any sense at all), its also an annoyance.