I think the possibility of multiple explanations has a great value beyond just providing a "better" explanation. They also allow a different mental model to be expressed, which in my personal experience was very helpful in learning new concepts in mathematics.

In school, you are often taught a very strict mental model based directly on the books and then hammered with very similar examples hoping you will understand it after the n-th one. But what lead the concepts to "click" in my head were often somewhat different mental models (which I think are different for each person). That initial mental model can then be more refined and adjusted to be more in line with the textbook one.

I'd rather read 10 explanations that are a bit different and the understanding with 10 examples than to read 1 and hammer that in with 100 examples.

It sort of reminds me of Paperscape [1] but more on the style of wikipedia since it invites you to edit it.

Organizing knowledge is way harder than it seems.

Instead of for topics, I would personally like to see this implemented for courses and their prerequisites (and perhaps the topics in each course) in order to keep track of your own learning or plan out what you would like to learn in the future.

[1] http://paperscape.org/