Every time you walk through the lobby, or near the back of the main building by Gasparilla Grill, you'll see some workers, some walls, and some less-than-magical construction materials. If your room is close to and facing those areas, it's possible you might hear some construction-related noise during the day. Otherwise, the rest of the resort should look beautiful.
We're visiting in August, and although I would love it if we got to experience the Grand Floridian for the first time in all its glory, I don't expect the construction to have an appreciable impact on our stay. I'm just grateful it's not expected to shut anything down (restaurants, pools, monorail, walking path again).