Ahh, you beat me to it! I rewatched the ep yesterday afternoon with Roomie, and noticed the mirrors everywhere and thought, "I have to go talk to misqueue about this!." At the bar, in the dance studio, in the apartment, in Santana's house...even the outdoor scene is full of wet pavement and fountain pools. Just generally speaking, mirrors add light and visual interest, but when you've got shot after shot someone fully framed in one, something else is up, something DEEP and SYMBOLIC. :P

What I found most interesting was that I don't think a single character looked directly into a mirror. Even in "Don't Speak", when Kurt and Finn are sitting directly in front of one, they're looking down and to the side. Even in your mirror-as-visual-conceit, when Kurt and Blaine sing into each other's faces from two inches away, they're not making eye contact. What's up with that?