Hi,
while I think the main idea about expansion was really good, I have several problems with final release.
Background quests:
1) Man getting his head cut off in front of Olgierd's house:
Mostly problem with dialogue and consequences. I don't remember now, but I think there was no reason provided, why they wanted to kill him. Dialogue is basically "Do you want to kill this guy?" with answers "Yes" and "No". There could be multiple endings like find out what he did and let him go or to kill him, maybe he could decide to help you fighting Olgierd depending on your responses. Let's say just more endings than "dead" or "alive".
2) Wedding:
Quests at wedding are good in my opinion, but it's quite weird to have to do them all. This include Gwent even if some players don't collect cards and don't play it at all. If there is player which expects serious dark world, I understand that beating pigs, getting drunk and rescuing guy scared of dog is bit out of Witcher style.
I think that there were more of those "funny for kids" moments through whole Wild Hunt, Hos and especially BaW that there should be, but with no offense and all the respect
3) Order of flaming rose
For me it felt invisible. They could be found in one or two places and main base had to be massacred in fight like 1vs40. Sorry if I am mistaken, but there were no options to infiltrate, spy or talk it out of them. Player just got quest to follow minimap, go to base and kill them all.
Upgrades - Runes and glyphs:
Just go and throw about 40k money at Offiery merchant, than another 20k for upgrades and that's it. Maybe it would be better to have more of specialized merchants on the map which would require something different than money to create upgrades, but in overall this would provide more possibilities to craft something.
I think that if there is only one source for non-(main)-quest items, in this case Offiery crafter, than it's bad desing.
Main story
1) Killing Offiery crew
There is optional quest to kill all the remaining crew from wrecked ship, but it has no consequences at all. It would be cool, it there were another Offiery fighters send to investigate, They would be split among Novigrad, Oxenfurt and Offiery camp, ask Geralt some questions and if they would find out, they would make some surprising attacks on Geralt. This would also harden ways to craft glyphs and runes, but there should be another crafters, as mentioned above.
2) Fail at every of Oddims's tasks:
As mentioned in the title, it would be cool, if all of the "three wishes" quests could end in more than one way each. For example, in second, player could find spell to smallen the house to inventory and than pop it in desired place, try to buy it in auction, act as he is rightful owner and so on. In third, maybe he could bring real rose ash, or ask those magical dog and cat for help and they would provide something.
Depending on outcome of every "wish quest" in chain, there should be somewhat different endings as in Wild Hunt. At least three or more "make-Ciri-happy" moments to get closer to happy ending. As right now, player can't fail at wishes quests and decides ending manually by dialogue option no matter previous actions. But there also should be moment at very end, when player decides side to join.
It should be more worked out I think.
3) Professor visit.
Linear walk through. Only dialogue is quite interesting, but changes nothing in result. Maybe this school environment would be cool for some Shani romance scene, but as it is already in the game, it should not be there again.
Overall
But in overall, as it was probably done in parallel and so with inconsistencies and in short time, quality is really high.
Main idea I rate 75% to 95%, but the replaybility, consequences, options and gameplay mechanics is about 50% to 70%.