Well...his main reason was his age. Now they have found a way to deal with it. And the new version of Data is much more human than the old version could have ever been.
To be completely fair, in some later season episode of TNG (“Birthright”, perhaps?) , Data had an aging program added. If that was the real deal, they should have let him age from that. So they had a way to deal with it already in place. They pretty much ignored that. He had an emotion chip in Generations. Largely, by that point, other than the pigment of his skin, he was more human than when TNG began.
Now I guess he can use contractions? Is that it?