This photo feels good to me: Why?

If ceiling lines would lead eyes to main subject in a harmonious way then the justice would have been served. Doesn't work for me as shown.

I think this would be an awesome photo for your collection, perhaps not for theirs.

My problem is with the ceiling - it looks like some sort of an alien ship getting ready to abduct the bride...

Crop the ceiling out.
It does nothing for the story of the photo.
This capture has a lot of emotion in the subjects, you can feel the energy of the event.
Sometimes technical perfection, and good composition aren't the ideal goal of the photograph. When this bride looks at this photo 40 years from now, it will still be a wonderful image.

I think this is a great shot. form I think you're dead right about the lines in the ceiling and edges of the dress giving the image a sense of energy and movement. I actually like the lights in the ceiling, and the shot has a sort of 1950's feel to it. It may not be an ideal typical wedding photo but I viewed it as a "dance floor candid" and as such I think it's excellent.

I like it. Remember, it's a MOMENT, if you can get a "perfect" shot (ie. exposure, etc) then that's great too, but the joy on granddad's face will be treasured by that bride for years to come.

To pose it, or to say, "oops, do that again" will ruin the moment.

The only suggestion I'd make on this one is to actually do the focus on the granddad, maybe even with the f1.4 and with the bride a bit blurry, then it's not necessarily about the bride, its' about granddad.

Let's face it, he probably won't be around in 10-20 years so to get a nice shot of him, being active (dancing), smiling, enjoying his granddaughter on her wedding day will be priceless.

I would wager that when the bride sees it, she will make a very positive comment about it.

I think sometimes the content of a photo is strong enough to take priority over any technical aspects, and should be judged in that light.