Hey, as a quest designer I can talk a bit about point 1:
I absolutely agree with your idea, and that's something we already use as part of our quest design (and have also used in The Witcher before). The one thing we never want is people to already know what they can expect from a quest.
Usually, when we pitch a new quest idea or story, we always look for an interesting theme, character moments, unexpected twists and choices and consequences for the player. The nitty-gritty of a quest comes later, once we have a good base idea.
So you can definitely expect that a character might die based on one of your decisions (even if at some point you thought you were doing the right thing - as in real life, sometimes things spiral out of control), or start to resent you based on your behavior. But on the other hand, sometimes things might even go better than you expected. As long as it's interesting all the way through, we did our job well.

If a quest has none of these interesting moments of choice and consequence, than as quest designers and writers we always look to improve it.
I do not remember - even a single time - when using axiie in dialogue had "bad" consequence.
We actually tried to do that sometimes. As an example if you use Axii against a group of thugs in White Orchard, the ones that are not affected can immediately tell that you're trying to manipulate their buddies with magic and will attack.
One of our newer quest designers actually used this in a side quest he sent in as part of his application. You were supposed to find and bring back two brothers in the middle of a forest. At the same time, your main story had you hunt a dangerous monster in the same forest, so it made sense to look for the brothers as well.
Once you found them, they didn't immediately want to return, so you had to convince them. You could use words, beat them up, or use "Axii", which you'd expect to work fine. And it does, they both start walking home.
However, later you found out that the monster you were hunting in the main quest tracked them both down and killed them on their way home. Since they were still under the influence of Axii, they just walked home without consideration for their surroundings, which made them an easy target. Maybe without Axii, they would have had a chance to run away.
That was a really nice example of how to use the player's expectations against him, because in retrospect this tragedy could have maybe been averted. So that part of the quest was actually a big plus for us!
