Now, I can't help but look at the normal ending as the preferable one. I would think along with the aesthetic design of the ships and quite possibly a merging of two races in the process, whether this has happened by this point in the story or not is not something I can guess at, but would be inevitable whether it has or not (or perhaps I misread something here and simple modification, and not outright merging, is actually all that took place)...
... I'd have to wonder what aspects of the babyeater nature and society that could be considered positive have been merged with the superhappies, such as a profound sense of tribal duty (arguably already existing in the superhappies, but more starkly expressed in the babyeaters), a very strong willingness to sacrifice one's own pleasure for the perceived good of the tribe and the whole (no more hiding from negative empathic emissions behind the superhappy confessors, well, quite as much), I'm sure there's more. At first glance, it looked to me like the superhappies basically ate their brains for their knowledge, but after a week of consideration, they would be just as much, no longer superhappies in the end.
What do they get from humans? Deception? Big beefy arms on the ship? I'm unable to say because I have difficulty separating my current perception of humanity from the evolved society in this one, but some constants stay true. Is it not a sort of evolution? A macrocosm of wanting to unite all people of differing perspectives and backgrounds for a shared goal, for the greater good of the whole? If you sat a human down next to our early ancestors, given the same backgrounds, would they be the same, or somehow different?
I know I'm far from the smartest person in the room, but the original ending seems to be a win and the true ending a failure. Blowing up the star and dooming all those people who had little to no say in the matter strikes me as more harmful and staggeringly less productive. The people in the first ending who commit suicide chose that for themselves, after choosing for their children, that was their decision entirely, based on a principle of what it means to be human, and not what it means to be a sentient being (which is why ending 1, imo, is less wrong than ending two, where a handful of people make that choice for everyone who could choose to opt out themselves, over their own opinion of what it means to be human). Just wanted to say my wrong-thinking piece because it's been nagging me for a week.
Just wanted to add it was a really thought provoking and fun read, by failure, I did not mean on the part of the author, it's his story, but on the part of humanity. Sorry to double post, probably won't see more from me, just found this a compelling read.