I don't think it's too small, but wondering if your art in the hallway (is it larger?) and the mirror could be exchanged? The mirror seems better suited there and the art would give your room a bit of a pop. Could also add wall sconces on either side.
[houzz=]

I love the mirror where it is, and the artwork adds color to the adjacent pale wall. Your chairs are beautiful.

Totally different thought....love the mirror and the size, but not sure I like it floating. So when I looked at the next pic, ah! Why not move it over a square and have it fit/tie in with the piano. No more floating and finishes off that area of your room, too.

If I were to move the mirror to the left, what would I do with the rest of the wall?

Nothing. Your molding is also considered wall decor and blank spaces are actually good things in rooms. And when you look at that second pic, see how the lamp shade almost becomes part of the wall decor due to where it hits. I realize centering the mirror made sense to create a balance in the room and that you worry the rest will seem neglected if you move it by the piano. I do not think there is a worry.

I really like this just the way it is. Good job!!!!!!!!!!!!!!!!!

I like it too!

It looks great. Don't change a thing.

My vote is to leave it as is;)) Looks great!!

Sorry abbyjean... let it float....

I would like to see the piano under it and the mirror a bit closer to the bottom trim piece so it doesn't look like a bullseye. Without seeing the other corners, I'm guessing I'd put the chairs in the left corner with the floor lamp, not the table which is a tad too tall for the chairs. Then I'd float an armless settee where you now have the chairs, adding a ceramic garden stool or a pair of them for a coffee table. Try silver to reflect the mirror or blue to pick up on the walls.

Deco I love the whole idea ....I would do same or a long bench with rolled sides instead of Estée

Setee

the molding on the wall makes the mirror the correct size - if there was no molding it would be too small

I wondered about the other corners of the room, too, deco.

What is your paint color? It is very rich.

The paint color is BM Kendall Charcoal. We absolutely LOVE it.

Can I ask where you got the mirror? My friend is looking for something similar. Thanks.

Absolutely! It's even more fabulous in person. :) Here's the link: http://www.lampsplus.com/products/kichler-teardrop-silver-and-glass-35-inch-framed-wall-mirror__x5777.html

I like it!