The tone of the sims is light and has almost no lasting consequences whatsoever, so any disabilities they add will be treated as a joke. The only way I'll accept that is if they add fake disabilities, like someone growing antlers or something dumb like that.
But what we're not gonna do is add in disorders/disabilities that real people go through and trivialize it.
The only thing I'd maybe accept are temporary broken bones; that way you guys can have your crutches and wheelchairs, but it won't be permanent and it won't mimic something much more severe. Mobility issues in elders is also common and an expected part of life, so canes would also be alright (we got that in Sims 3, I think). Anything else would have to be handled with care, and I don't trust the sims for to add them in responsibly.
Edit: I also just don't want to see people making fun of sims with autism, depression, anxiety, or any other mental illness. I don't want to see people forcing wheelchair bound sims or other physically disabled sims on foundations and then taking away the ramp (there were load of videos with people putting sims in pools and taking away the ladders just to watch them drown). That is something that will happen if we get these disabilities, because people suck.