Actually, the AI does obsolete it's old designs. It does not use the HIDE OBSOLETE button, though. So when you poke your nose in to see what its doing, you'll see all the old designs.
I agree that the AI redesigns far too often, apparently for no reason. It's weird. I guess there are basic routines that get called every time the AI for a particular race runs.
Also, there seems to be a hard-coded set of design types for the AI. YOU can create every type of ship that you want: Scout ships, Remote mining ships, etc... but the AI only understands the design types that the game comes with. Attack Ship, Defense Ship, etc. I tried to create a "Repair base" type to put repair bays over at least some AI shipyards. It would not accept this type. So, I changed the type to "Space Yard Base" and just used the NAME "Repair base" and it accepts that.
BTW, I wonder why "Defense ship" was not in the default AI designs file? I added it and it does make the AI smarter about defending itself. Hmm....
[This message has been edited by Baron Munchausen (edited 15 December 2000).]