In the rush to all things digital, you see the limits of the technology in areas like that. If you skip HD and move back to some old 480 line display you might see the old smooth images. But if the content is digitized, you will see pixelation in high motion areas.
Why this is not considered an issue is, well, because to cure it we would need about 10 times the digital data and most stuff looks fine. Maybe this is the old quantity over quality again issue.
I first bought a Sharp 52" LED TV and it had a phenominal picture when still or slow but when I watched sports or even shows with a fast movement I got pixalation, blur, etc. I tried multiple different settings and called Sharp with no changes so I took it back.
I asked the Best Buy team what was best for watching sports, they mentioned plasma so I bought a Panasonic P50ST30 and while the picture appears a little better I am still getting some "Ghosting" around the players when they are moving and still not a crisp picture.
I tried different settings with each and called my cable company who of course says that I have a strong signal and it is not their fault?
Any recommendations short of getting rid of my cable?