There's the recurring theme of what makes a ship too uber and the uber vs standard debate (which is highly entertaining in its own right - long may it endure).
There's also the question over how one justifies, for example, the improvement of a Cobra III to a Cobra IIIe (or whatever your favourite variant is this month) - where all the stats have been improved and the only negative is a higher purchase price.
I'd like to propose a mechanism to justify this - while I'm sure it's not possible given the current structure of Oolite, perhaps it's worthy of consideration when the core is updated.
At it's simplest, allow attributes of a ship to degrade over time. So in other words, you Cobra IIIe's top speed of 0.375 when you bought it degrades by whatever function you like as time goes on, so for example, after 5 years, you're only getting 90% of the 'new ship' top speed (the actual numbers would need to be determined as a result of balance testing).
This pseudo-degradation would then provide the illusion of technological progress. Presumably, a Cobra variant with a more recent design/build date should be faster than the standard Cobby of 3200 vintage.
The same could go for other components - ECMs could become less effective as time goes on, necessitating the need to upgrade to a better one; older model missiles become less effective; older, less effective components become cheaper in the shipyard as newer, more expensive components become available (and these in turn would degrade as time goes on).
Such a mechanism could also justify the frankly outrageous price being asked for a Fer de Lance - not only are you paying for the genuine walnut cockpit inlay and sumptuous leather seatings, made to measure for all space faring species, you also get rock solid reliability and longevity (i.e. the ship's degradation function is much flatter than, say a cheap as chips Adder) - and from a gameplay point of view, it's that longevity that the player will notice over time.
I don't know....this is just another one of my ramblings while I try to avoid doing actual work
