I have these builder grade mirrors in our new construction home and I've found a ton of ideas on Pinterest on how to make it look better. Here are a few pictures.

Also, another idea is that you can remove it and get it framed, then use it in another room in your house.

Jan's right, it is unlikely to be removed in one piece. You could smash up the pieces and use them to create a mosaic piece of wall decor.

Is your contractor paying for your new mirrors? All kidding aside, you can tell how glued the large mirror is by sliding a large piece of poster paper behind it and see if it moves. Some times they do not glue but just rely on the track and clips to hold it against the wall.
I had a glass company come and take down my builder mirror. It was worth the $100. to have it removed and disposed of by some one else.
I have two framed mirrors now, with sconces in between, but it is not as bright as before with the natural reflected light.
You can dress up your large builder mirror with those glue on frames or perhaps even hanging a framed mirror on top. I think you must plan well for that.
Good luck with your Reno and enjoy the process!

You could look into https://www.framemymirror.com or http://www.mirrormate.com if you want to consider keeping it.

Thanks a lot for great advice! I am gonna check out those two websites, and like you guys said, if that doesn't work then move on. No advantage in moping about it :D

Nice framed mirrors can be had for relatively small investments. Then, if, as you hope, the large frameless ones come back into vogue in a few years, just move the framed ones to another room or donate them to Habitat Restore or Goodwill (for a tax write off too!)

My contractor has removed several with no breakage. He removed mine. Habitat does not want it. Would like to the purpose but may have to break it.