I don't think we should jump to conclusions on whether or not Larian has settled on Karlach's ending being tragic or doubling down on what they have already. The article that was posted is only 5 days old, and mentions Karlach's new epilogue scene explicitly so this is obviously after Patch 2. Swen in the interview says that they're working on a new optional ending along with epilogues for the other characters, he can't simply be referring to the "new" optional ending that we just got since that had already been released AND the community expressed its displeasure about it.
Larian doesn't usually publicize what they're working on and is pretty cagey about what they're adding to the game, so the fact that Swen is hinting at a new ending at all is pretty big for a company that doesn't post what's in a patch until 2 days before it drops. Larian prides itself on listening to feedback, so doubling down on one of their most requested features to be changed would be an illogical move, especially when the in story rationale for it is so shaky. These things take time, and they have a lot on their plate right now. We can express our displeasure at what we have, but let's not get all doom and gloom until we see what else they release.
