What I say below may seem harsh but I say it only because I care. Because you're the best developers ever and we all want The Witcher 3 to be as close to perfect as possible. Thank you for reading
1. The story: In one of the gameplay demos, when you're following the griffin, you stumble upon some bandits trying to rape a woman. After you save her, the dialogue doesn't make any sense at all. She talks as if they just met at a restaurant. And the hint that sounds like she is a romance option... All doesn't make sense.
And all the quests we've witnessed are about you doing a favor for someone in return for something. Just like Skyrim. And so few dialogue options.
2. The Combat: Every single enemy Geralt kills in all gameplay footages has a part of his body cut off. Every single one! This feature has been so overdone in my opinion and I don't think this is Geralt's style. In the books he only does it when he's angry. And he usually isn't angry. He calmly hits his enemies in the arteries. Speaking of anger, Geralt showing an angry face before he kills the griffin? Seriously?
Geralt is not an angry Jihadist.
I read in an interview that enemies will attack Geralt at the same time. But in the demos enemies attack one by one, not all together. And I hope this combat is put on extremely easy mode because it seems very easy. The AI is stupid and you deal so much damage.
3. Simple lore things: Geralt is no longer White Wolf. His hair color is now gray or black. Ciri wearing high-heels? Seriously? And all the cutting people's hands and heads off. Just keep with the lore as long as it doesn't hurt the game.
Please don't overdo things. And let consequences make sense. Don't give me 100 clues that say that creature is evil and when I kill it I find out it was about to save the town from danger. Don't make consequences that don't make at least some sense.
The 3 golden rules are:
Trust the lore + Don't overdo anything+ Be real
Of course alot of these may only be like that because the game is still in progress.
Good Luck