The Quotes Wiki is the solution to that problem. This is the place to house any and all quotes related to a given trope. The main wiki article can then feature the pithiest or most exemplary quote, and put the focus back on the actual article.
So, if you find a really, really good quote about a trope, and you see that its article already has a bunch of quotes, just start a page for that trope in the Quotes/ namespace and move the extras there. If you're not sure where it should go, try placing it here. There is also this forum topic that deals with quotes.
And for the love of all that is holy, try to follow the proper quote formatting.
The full list is available here.