I dunno, as much as I like Emet I wouldn't want a potential codex entry to describe his darker actions in fluffy terminology. You could describe the formation of Garlemald and the Allagan Empire as a 'community building project' which sounds nice and is technically correct but it wouldn't really do his character justice in the same way that downplaying the Sundering and its effects doesn't align with Venat on any meaningful level.

I don't factor in character popularity to the same degree, either. Sylvanas was exceedingly popular in WoW and her continued presence in the story - as well as the constant downplaying of her various misdeeds - contributed heavily to turning people off of that game's ongoing story.

The other elephant in the room is that the codex will be cited as 'mommy did nothing wrong' and fuel more discussion about how the Ancients were stupid and Zodiark was a 'blood god'. Which is deceptive framing and not in alignment with the actual story being told.