Chromecast is exactly built for streaming video to your TV. The problem wasn't w/Chromecast but with my stream from DirecTV. Even on my 15" laptop the picture quality was jut okay so when I viewed it on my 55" TV it looked pretty poor. I've played high quality videos on my laptop, streamed them to my TV via Chromecast and they've looked just fine.
Netflix, Amazon, Hulu, HBO GO, etc., all look fine when streaming so the problem was definitely with DirecTV's stream.
No. Chromecast wasn't built to stream video in the way you were using it for NFL Sunday Ticket.
You stated the stream was OK on your laptop, but it sucked when you cast it to the TV. The stream from Direct TV was ok, if it wasn't it would have sucked on your laptop as well.
When you stream NFL Sunday ticket to your Chrome browser, data is coming from the direct TV servers, to your network, to your laptop. When you cast that to your TV you are then retransmitting the same data from your laptop to your Chromecast across your home network. As a result you are in effect streaming it twice and clogging your home network with double the bandwidth and taxing your network adapter with both input and output on the fly, all over the air with Wi-Fi. Its terrible.
This is not what was intended by the Chromecast. Sure you can "do" it, but it works best for casting your browser or desktop to view static images.
The reason it works well when you cast a video from your laptop to Chromecast is because I suspect you are casting local content. I can drag a video file into a Chrome browser and cast that with decent results.
The other services you mentioned (with the exception of Amazon I believe) have purpose built apps specifically for Chromecast. When you hit that little cast button on Netflix or HBO or whatever, you're sending a signal to Netflix to send the video data DIRECTLY to the Chromecast stick, using the native Chromecast capabilities and compression techniques. Therefore, it doesn't go to your device and then cast to your TV. Your device only is the controller for the stream at that point, but no data goes through it, and no data is rebroadcast.
The video stream goes from content provider, to your network, to your Chromecast in one fell swoop, just like any other video you would stream on the internet.
Like I said, Direct TV's stream was great on my laptop, but I made sure everything was hard wired..the network and the video output. I controlled it with a wireless mouse. It was well worth it.