@Simulator4, thanks for not using cheats. I just wanted to create a SuperSim for other players but since people could do this in a few minutes I don't really care (and thanks to missing challenges there are already quite a few of them in the Gallery). But this is not the only reason. There's also the fact that weight/fitness won't revert to the original shape or that you get traits because of how you play (e.g. Loner from not socializing).
Or... toddlers! Not because they're cute and adorable but because they came with their own set of skills in previous games and in my case creating a SuperSim also includes maxing child/toddler skills.
And finally, I'd like to know what's in those tray files. You could delete the heavy/encrypted sgi/hhi without getting any issues (except you have to save her again before uploading) or missing features). While in 3, I could tell you the meaning of every single byte in my ultimate household file.
But let's see how this'll evolve till Christmas (after which we can't get our rewards for buying TS3 games anymore).
Or let's just say it's because TS3 skills come with challenges while TS4 ones doesn't.
btw, I don't know of any skill cheats in TS3 - just a few objects or mods. Which ones were you talking about?