Now Construction Strategies work strangely. It is like AI stubbornly wants to use only one design for all its life.
I suggest that...
AI should choose what to build with some variation, not only the most expensive design, but all of his options from time to time, maybe on random.
Now AI treats designs which are repeated on several tiers as highest tier design, but that makes no sense. The only time you place your design on several tiers is when you want it to remain on several tiers with other designs, not when you want only that design to be built, you can just make it the only one then.
It would be cool to have some options to make AI behave one way or another. For example, set some priorities, prescribed building placements, building combinations, fleet patterns...
P.S. Steam discussion.