Even with the new stuff, Alex never quite comes off as the piece of shit that Andrew wants him to be. Kind of annoying? Sure. Pretentious and spoiled? Yeah. But never outright awful. All the stuff that parallel Alexes do is stuff we hear about off-screen. It's emblematic of the biggest problem with Alex as a character. Lots of telling and not showing. We hear about how parallel Alexes have fucked up other characters (Ditching Vella for a younger girl. Kissing Michael in one reality and trying to kick his ass in another, etc), but the main Alex is dickish at times where it makes sense for him to be salty. Rory lied and he's kind of in the right to be shitty about the waste of time and the fact that they almost died.
I'll say they do a decent job of trying to work with what they've got at least. Like making it clear that Alex is supposed to come off as a bit of a creep and fetishist for his Semi obsession. Which is sorta there in the original release, but conveyed in a way that is so subtle it might as well not be a factor. I get that, as a writer, you don't necessarily wanna spell every little detail out, but YIIK was often times vague to the point that I wouldn't have known some plot elements if I hadn't followed the Allansons on twitter.