It just felt cheap and rushed to me, both when I saw it in the theater and every time since. And it wasn't just the FX, it was the story and most of the characters - I couldn't tell nearly anyone or anything apart for years. It felt like they'd expended so much effort in the idea of how to follow up one of the biggest action blockbusters in history, got nowhere due to bureaucracy and backbiting, and then finally threw a bunch of (IMO) inferior and bland scripts in a blender and rushed it out to meet a date. By the time they started shooting they'd burned out. And of course Fincher will probably never talk about it or be associated with the franchise again, which is tragic. Imagine if it had been a fraction of the film that his other '90s output was.
I'm not necessarily grieving about Hicks/Newt/Bishop after 30 years, I'm tired of that old wheeze and I'm not for Blomkamp's movie at all, but I do think it was a mistake and poisoned the well. If Sigourney really wanted a break you could always have taken a cue from Dark Horse and set the next film 10-15 years later, cast a young star as the adult Newt and bring Ripley out of seclusion. Or just say they all went their separate ways if it's going to be Ripley solo. Either way this is all wildly OT.