Sulu losing his legs is from GOD THING, not TITANS. I saw a show on KTVU Channel 2 in bay area about trek fanhysteria in 75 or 76 that had GR talking about his movie idea (TGT) and he mentioned Sulu getting bionic legs.
I remembered a bit more about the titans story (again, whether it was her starlog stuff or the making of tmp book, I don't recall.) New Enterprise Capt was named Westlake and I guess he tries to recruit spock for the mission unsuccessfully. Then, Spock joins up after having this vision shown to him.