The curve fad will be over by next year, and you won't even see them anymore.
Nope curved has been around for a long time. But the main applications has been in home theatre or large screen projections.
What we are seeing is the trickle down of high end out of reach tech that is coming to the mainstream consumer.
I have a 1080p 3D projector with 110" screen and to be honest I never use the 3D. It was a novelty to watch Gravity but it really doesn't add much. I find it detracts from the movie. It's like watching a movie with sunglasses on the colours are all fucked up.
As to why the 4K TV looks like shit..... can you describe it more?
Are you having what some call Soap Opera effect you are watching a regular TV show like CSI but it looks like it is Young and the Restless? IF that is the case go to your menu of your TV and try disabling some of the picture processing features. Do one at a time and see if it makes a drastic change. I had to do that for my TV..... it had some sort of motion feature forget what it was called but when you disable it then it looks more like how TV normally looks.
Do you have anything that can play 4K stuff? I notice they are selling disc players and movies in 4K but the selection is small. If you do that could be a way to test it. If you have a computer that can handle 4K maybe buy a digital copy of something in 4K to try on the TV.
But honestly in my heart of hearts try the video settings first..... don't worry about contrast, brightness but more name brand video processing options,