Honestly, when it comes to starships? I don't have a clue. I'm still working my way through 6.018. I've been getting home around 7 each night, so i'm falling behind the updates. I have definitely been avoiding too much criticism on that subject, and offering commentary on other subjects where I've been more comfortable.
I can say that I feel I no longer feel like I'm making a huge sacrifice unlocking two lines of MK3 Starships (plasma and bombers) and therefor raiding eye systems doesn't feel anywhere near as prohibitive anymore. Heck, thanks to cloaker starships and mobile repair, Mk3 Heavy Bombers and Mk3 Plasma Siege Starships can even sometimes clear out their direct counter guard posts.
The debates raging around K costs are significant, and honestly, I feel that maybe too many different balance discussions are going on to get a good feel for where things will actually end up - other than with thorough playtesting and feedback after they're implemented.
Before I go further, I want to emphasize that everything below this line is written with dual Defensive AIs in mind, and not the regular gameplay that you get with more middle of the road or offensive AI types. Aside from a game of fallen spire, starfleet commander, and mad bomber I put aside to take on the max AIP challenge, my experience has not caught up with the game as it stands now, with weekly updates. My hours (less than ten, more than three) of non-turtle AI hint that the experience is probably very different to what I'm reporting below. I'm honestly not comfortable commenting on starship balance, but I do hope to see if I can rope my usual team into a co-op game this weekend and try a faster paced marathon or two.
Using starships to take out Eyes is actually an interesting proposition now. Defensive AIs actually promote a significantly different playstyle and much more considered approach to cracking mk3 and 4 systems than before, particularly with the overlapping positions of force fields, fortresses, guard posts. I repeat: I'm actually having some fun facing both a turtle and a fortress baron, something I would have not believed possible a few months ago, when guard posts were uninteresting, starships fragile and k prohibitive, guard posts could cloak themselves, and so on. In a world where every game was against dual defense AIs, I think the game would remain strategically interesting even if fleetship K costs were nerfed to similar levels. Clearing these AI Eye systems now feels more like a puzzle than a punishment game. The only problem is: the answer is always starships, even if fleetship hordes have the right immunities, so why bother ever taking my fleetships on defense? They're more useful guarding my flanks. A variety of system-restricted types of AI super guardians could actually add to the variety of puzzles I have to solve, and if I invest in fleetships more, well, I have a reason to try and use them even in less than ideal circumstances.