I think they removed some of the achievements that didn't work and couldn't be fixed.
A lot of people put a lot of time into working out which achievements could be fixed a couple of years ago and had a SimGuru working with them and they fixed a lot of the broken ones then and then removed those that they couldn't fix.
Thanks for this thread as I have recently decided to get back into trying to get a few of the achievements and having an idea of what is required to get them is very helpful as it saves so much time and frustration with some of them. This was especially the case when some of them were so broken they couldn't be solved. If I couldn't get an achievement fairly quickly I used to get frustrated and wonder if it was broken.
One I tried to get over and over and over again and always got my Sims to do what was required but never got the achievement was one of the supernatural badges that involved having a vampire and witch parents with a ghost, werewolf and fairy children to go to the park together (or something similar - can't remember exact details now). I think that was one they couldn't fix and deleted.
I'm currently half way through making 15 witches to try to get the badge where a male sim has 15 witch partners and breaks up with 14 of them.
I'll post pictures later of all the witches I made ( because I like posting pictures :s )
