Now, I haven't read the Zelda wiki article, but there is still no absolute proof that he was searching for Navi.
I base this idea on the Beginning and the end of Majora's mask.
In the beginning, it only says that he was looking for a friend ( I'm not exactly quoting here but) a certain friend that, after he had taken his place among legends, left him.
Now this automatically points to Navi. But, at the end of
MM, Tatl speaks. She says something along the lines of "We've both found what we were looking for. I guess it's time for you to leave now, right?"
This is incredibly strange, seeing as Link never found Navi, unless Tatl is the Termina version of Navi, but that's not my theory. My theory is that, most simply, Link was looking for a friend. Now, I know what you're thinking. "Link had plenty of friends" right? Well, let's dive into a bit off psychology... Link, being used to being a hero, most likely felt unfulfilled after he was returned to Hyrule in the Child Timeline. He probably wanted to find Navi, but hat he really wanted was to be a hero again.
Thus, he found Tatl, saved Termina from Termination, and became a hero once more. He found what he was looking for.
Also, he went on this search to further protect the Sacred Realm. If he had stayed there, there would have been a possibility of Ganondorf, or someone else, taking the Ocarina of Time and entering the Sacred Realm. If he left, then no one would get the Ocarina and the Triforce, all together, would be safe.
Afterthought: Even though the Triforce would have been safe anyway since he the Triforce of Courage with him, effectively breaking it, one to Zelda, one to Ganondorf.