On the zenith/spire stuff: I've never been comfortable with stuff having sub-one multipliers, let alone steep ones, let alone one that causes a ship to do effectively negligible damage to a common type (like fortresses and the old zeniths did against polycrystal). The game used to have all kinds of crazy stuff like infiltrators getting a 100x multiplier vs fortresses and so on. Nowadays I try to not have multipliers greater than 10 in the interests of actually being able to balance stuff and reason about the numbers, etc.
Needless to say I'm not happy with the way fortresses are now, but I do
try to restrain myself from changing stuff simply because it bothers me unless the players agree or it really is a huge problem
Though I think there is fairly widespread agreement that fortresses usually being a case of "clear out nearby stuff that can kill with bombers, swarm fortress with bombers, wait several minutes" isn't really the kind of fun it could be. But more fun than fortresses completely trashing
every ship the way they do anything that's not polycrystal nowadays.
On the spire side, another thing that became a huge problem earlier in the game's development was so many units having
enormous range. How could each planet not just be 1 big fight in a case like that? Perhaps we'll go back to simply being ok with each planet being 1 big fight as we haven't really succeeded in achieving the battlefields-within-battlefields feel, but on the other hand I do think we achieved enough of it that just totally ditching it would be a mistake.
All that's not to say that zenith/spire ships couldn't be made more interesting in the future, and I have some ideas, I was just making them at least more
useful than they'd been since the more outlier stuff had been removed.