Adding disabilities to The Sims would be good idea on paper. It adds extra challenge for people who want it and lets people who want to make themselves in the Sims finally be able to do so accurately. On the other hand, adding wheelchairs is going to take a lot of work. it won't be as simple as adding a new object. They'll need new animations for doing almost everything. Every animation that an able-bodied sim does while standing will need to be remade for the wheelchair sim, and many animations for the able bodied sim will need to be added for when they interact with the wheelchair sim. New objects like wheelchair ramps and extra wide doors will need to be added and existing buildings will need to be modified and wheelchair accessible vehicles will need to be added. All that just for one type of disability, and they'll probably want to add other types too, like blindness which will need it's own animations. It'll have to be an expansion pack sized update. If the devs think they can do it all then I say more power to them, but it won't be easy, cheap, or quick.
