Hi CC,
It's a mix of things.
Some complaints are legit. And in the first instance there were problems with Steam aswell, leaving a lot of players waiting to properly start using the game.
Other problems are indeed because people do not inform themselves about the system specifications. And the game does require a bit of 'good pc management' aswell. Maybe a bit more than some other games that work 100% out of the box for everyone.
It's debatable, but the majority of players seems to have little problems besides known bugs or missing features that they would have wanted (bugs will be ironed out, a lot already have been). The number of complaining customers on the forum and on the support channel compared to total units sold would suggest it looks a lot worse than it actually is.
The thing with reviews and forum topics is, that 90% or more is always the negative kind. People are quick to complain, but if they're happy, they often don't come here to say that, they simply keep on sailing happily.
And if you do buy it, and despite your pc being up to the task, you can't get it installed or run into a major showstopping problem, then I'm pretty sure you'll get a refund.. (if you don't wait too long of course.)
Regards,
Fred