I actually don't have very high expectations regarding the reviews. I think the game will maybe not be rated as high as it deserves (in my opinion). Witcher games are still niche games after all, and -besides the downgrade-discussion- there could arouse some criticisms. For example the size of the world vs. density of content: W3 has a more realistic attempt here where you don't find loot chests, cave entrances and quests behind every bush, some people could still consider this to feel "empty" and they could criticize that the game does not really encourage free exploring but rather running from one POI to another. While i may like the more realistic approach and don't really like the idea of having free loot behind every corner, others may not. They might say "Yes, the map is huge, but it feels artificial and empty - you have to use your horse a lot, and if you don't, you might find yourself wandering almost empty roads and woods for a quite long time".
They might also mock the AI, that isn't enough "next-gen", the crafting system (alchemy as a hunt for alcool), they might ask why there are so many different weapons you could use but won't because Geralt is a sword fighter after all - and thus complain about the lack of variety in combat-styles....
In the end, Witcher games aren't for everyone. Witcher titles aren't Elder Scroll tales. There is no housing, no guilds to join, no factions to side on, no random quests, there is no content without a reason. So W3 will not suit every RPG-enthusiast in the world, and that is fine.
As soon as we will see those reviews, and during the first week after release, we will have all those questions and suggestions here again: why is there no stealth combat? Why can't i play Geralt as a dual wielding axe/sword/whatnot fighter? Can i buy a house? Can i marry Triss and have Kids with her? Why can't i rename my fucking horse? Why isn't this a sandbox game where you can depopulate whole cities and villages if you wish to?
Be prepared. Release is coming.