I don't think your counterpoints work. If you go down that route, Minthara and the goblins offer you a save passage through the Shadow, which none of the other options can
This is probably supposed to be one of the unique things about the path, but it's not actually unique at all. The only unique thing about it is that the game offers it to you ahead of time. You can do essentially the same thing without siding with the goblins at all. The only real unique thing about siding with the goblins is being able to have sex with Minthara which in the game's current state is a pretty awful writing and design choice (and just starts to look creepy looking back at being told in Early Access that she's the reward for evil, they REALLY meant just her very specifically).
In terms of metagaming anything, like yeah but this isn't a tabletop it's a videogame. The design itself is ENTIRELY too drastic about how much content is closed off for how little you get in return in any scenario where Minthara is in the party. Add to that how much of her reactivity is Dark Urge specific and it gets kinda bonkers. That recruiting her by being neutral still locks you out of nearly all that same content is WILD, especially when signs of a big scrapped contingency to keep a big portion of that content is still in the journal and that's where the user experience perspective just dives off a cliff.
And personally I just really can't let go of how lopsided she is compared to Halsin. With Halsin being totally fine with you murderhobo-ing your way through the grove why the hell isn't Minthara accessible without a huge slaughter happening whether off-screen or led directly by you? Her circumstance is exactly what a typical good-aligned character would think about trying to help with if they found out even just a little about True Souls and their tadpoles. But obviously for gameplay purposes it could just be as simple as the game flagging the quest as complete without flagging her as dead on knockout so she carries forward. I'd rather a small programming change like than a content expansion even if they went full Definitive Edition on her, simply because she's so interesting that the kind of content a lot of people want to see is just too much.
