Re: making it a solo instance. While I agree with the idea, in practice, I think it might take more work than they'd expect to change it. As an example, think of the search lights. Will NPCs be tuned to know to turn them off? Or, will it more likely be that the player will have to be in charge of all interactions? What about all the cannons? Can NPCs figure out how to use those? What about the entire Livia fight? There's a number of "boss is effectively invincible for now" parts scattered around here, and it'll take a bit more tooling to get NPCs that know what they need to do, I think.

It won't be so easy as just "run the dungeons with NPCs." That would be either overly complicated, or, in creating the solo instance, will have to be so modified that they are disinclined to put that much work into doing so.

Making it solo sounds easy, but there's probably more effort involved in that than is immediately apparent.

It'd still be nice if they did it. As someone said a while back, once done, it would likely be the final permanent solution; no more band-aid fixes. But the evidence seems to be that they have no desire to dedicate much resources to the cause.