Welp, having played through 6.3 at last, I have to say...
The hate is pretty overblown. It's not great. Compared to even previous "middle of the story" patches, such as 3.2, 4.2-4.4, and 5.2, it's probably not in the upper half for me. But it wasn't terrible.
The writing surrounding Zero is all kinds of hamfisted, mind you. And they really overdid it with the hat tipping—it's cute once in a while, but doing it 1-2 times per conversation is excessive. But I like her. I like stories about hurt or broken people learning to live again. There's something genuinely sweet about it.
I also would've appreciated the writers not shafting the nuance in Rubicante's motive immediately, and instead letting it simmer for a while. And to be frank, the entire "Why is Azdaja in Garlemald? Why did Cagnazzo say his work was done when he died? Oh lol it was all a trap." thing was kind of an idiot plot. The worst part about it is that you could have all the exact same story beats without the Scions collectively sharing one brain cell.
Step One: Have the characters discuss Azdaja's sudden appearance in more detail. Have them recall that moving physical bodies through voidgates is nigh impossible if the gate is too small.
Step Two: Have them conclude that either a massive voidgate must exist in Garlemald, putting the entire region and indeed the whole world in jeopardy, or a much smaller piece of Azdaja had been passed through a more familiar-sized voidgate. Such as, say, one of her eyes. Either way, they will still need to investigate, but at least this way they aren't stumbling into an obvious trap.
Step Three: When Cagnazzo lets slip that his death achieved something, have the characters discuss this and realize the obvious: This was a distraction. But getting back to Thavnair is not immediately possible—they have no aetheryte access in this remote a place. They can send advance warning to Thavnair that something is amiss, but...
Step Four: The efforts to stop Rubicante's entrance into the Source would obviously be met with failure. This could then lead into the reveal of Rubicante's character by having him destroy the voidgate, but not harm the guards when he escaped.
Edit: Also, the end of the last quest is in line with my "idiot plot" complaint. We just came back from encountering a voidgate, opened through the use of a dragon's eye, in a place where doing so is significantly easier than elsewhere. At the very least, that should be the first thing the characters suggest, if only to refute it as a possibility.