Unrealistic expectations? Samsung 65MU8000 (1 Viewer)

[John_Bilbrey]

So after much reading and looking, and watching sets in store (which I know isn't a true example of what it will look like at home), I ended up pulling the trigger on a Samsung 65" MU8000 from Sams (technically a 800D) and brought it home. Followed the setup/calibration guidelines from rtings.com and I have to say, 4K content from YouTube looks amazing. Netflix and Amazon content looks good as well. Here's the rub - we have streaming TV service from Sony (PS Vue) which is only broadcast in 720p if my memory serves correct. Content here is well...lackluster. Is there anything I can do to improve this? For example, when watching GoT, the blacks look very pixelated, for lack of a better term. I'm coming from an 8 year old Samsung plasma for comparison sake. I have the PS4 running via HDMI to my Denon, and then to the Samsung. Samsung returns via ARC to the Denon.