He wants to have more choices, so this situation wouldn't arise.
Unfortunately, there's simply no such person.
Sun Wukong is the sole option.
There is another choice, which is Yang Jian, likely able to replace Sun Wukong.
But, from Lord Taishang's point of view, Yang Jian exudes righteousness, more likely harder to convince than Sun Wukong.
If he senses something amiss, he'll definitely drop everything immediately.
As for someone like Sun Wukong, who'll continue to do with a little benefit, that's impossible.
"Say no more, if you want to be the master to Old Sun, this matter is dropped, I'll immediately return to seal the mountain, emerge a hundred years later, if desired, Old Sun is willing to lend you a hand. I believe you won't do anything that endangers the Three Realms, most likely you'll be doing things beneficial to the Three Realms."
Lord Taishang nodded slightly, smiling as he said: "You do understand the old Taoist quite well."