I think the main issue is that people aren't really understanding what it is. Even Cas at Fextralife is basically marketing it as an MC with more options. We don't know what happens as you begin to 'recall more of your memories' as you progress through the game deeper and deeper into Act 2 and 3. It seems to be consensus that you will carry out atrocious acts without any control over your character. There will be moments you can intervene and obviously decide to choose how far to go, but other moments you will not have control.
It seems there is simply not enough information as to whether this is a character that is "basically Tav with a backstory and more dialogue/choice options that lean evil" or if this is a "primarily evil playthrough but you can control how evil it is going to get", a lot of people are speculating that it is former, but it could just as easily be the latter, in which case if they are expecting a goodie two-shoes Tav with more of a backstory and some strong redemption arc then they may find themselves quite disappointed.
Fextra has seen the game though, while the hivemind forming a consensus and preconceived notions about the game haven’t… there isn’t enough information, but I’m leaning towards the guy that has actually played the game versus people that haven’t.
Fex has seen some of Act 2, and some of Act 1, he beelined through Act 1 to get into more Act 2, he spent, as he claims, roughly 8 hours in Act 2, he also skipped over the 33% additional content in Act 1. This means he played a very tiny subset of the overall content as the Dark Urge, which means his opinion that is it is just 'main Tav with more choices' is based on a relatively small dataset of information. I like Cas, love Fextralife and use it frequently, but I am very skeptical of his claim on this. If he was allowed to play all of Act 1 and Act 2, that would be a very different story, but 8 hours is pretty marginal in the grand scheme of things here.