To the end of DGSD, only five people (Kiu Fung, Siu Yeun San, Mo Yung F'uk, Mo Yung Bok, and Kau Mor Tze) knew that within the Shaolin Temple, there lived a humble Janitor Monk who, for his unassuming status and appearance, was by far the most powerful fighter ever to appear in the Jin Yong universe. Because it stayed that way, not much within Shaolin or greater wulin changed after the Heroes Conference at Shaolin Temple.
But what if, in an alternate scenario, the Janitor Monk had exposed his great abilities to the wulin public? What if he showed up in front of the assembled wulin and demonstrated his great abilities by casually subduing the aforementioned five elite fighters as easily as they would any ordinary fighter?
This creates an interesting set of dilemmas for Shaolin.
1). Do they punish the Janitor Monk or not? How?
Shaolin had some pretty strict rules about who can and cannot learn their martial arts. While we're not certain that the Janitor Monk actually practiced Shaolin martial arts, chances are he probably did. Assuming he did, he would have been in violation of Shaolin rules because he was certainly not authorized to learn the skills that he did. In so doing, however, he prevented a catastrophe at Shaolin...and brought great pride and honor to the Shaolin Temple by demonstrating that their martial arts are indeed the most powerful in the world. Does Shaolin really want to punish him for that? Even if they do, how would they do it? The Janitor Monk was so powerful that all the other Shaolin monks combined would not be able to injure him. They couldn't punish him even if they wanted to.
2). Do they promote the Janitor Monk to a higher rank...perhaps even Chief Abbot?
The suicide of Chief Abbot Yeun Chi left Shaolin without a leader. Would that next leader be the Janitor Monk? In terms of martial arts supremacy and Buddhist enlightenment, he's an obvious choice, but there are several problems. First, he is unlikely to be interested in taking on any such office or responsibility. The Janitor Monk was completely without ambition, and he is unlikely to be willing to take on the hassle of administering Shaolin and wulin affairs. Moreover, just because he was a great martial artist and an enlightened Buddhist doesn't mean that he was a great administrator or leader. The man spent his entire life in meditative contemplation; his social skills would be zero.
3). They need to do something about him, but what?
If they don't throw him out of Shaolin (can't see how they'd do that if he doesn't want to leave) and if they don't promote him to Chief Abbot, what would they do about him? They can't just go back to the old status quo of having him be a janitor at the temple. Now that his great abilities are known by all, EVERYBODY in wulin will want a piece of him. Some will want him to become their martial arts teacher (fat chance). Others will foolishly try to challenge him...to see for themselves if he's really as powerful as he seems and to try to overcome him (yeah, fat chance, but people have done stupider things) for personal glory. Yet others might want to make him their tool for their own ambitions.
The Janitor Monk had probably considered all of these things, and they're probably important reasons why he never revealed himself except to those five fighters in an emergency situation. Still, had the Janitor Monk gone public, it would have opened a whole can of worms.