I've noticed the grain as well, and I think it's probably intentional (esp if I'm noticing it on SD!)
The New Caprica arc is painful, but I think you really need to watch it to understand the rest of the series. Not that I've finished it...
I watch “Caprica” when it first came out. Very different feel but I liked it a lot. It was nice to get the beginning of the back-story for the whole series. The thing I like most about the new “Battlestar Galactica” is that they started with the intent of telling a story rather than just having an ongoing series. It’s the same thing I like about most animie. However, the downside is if you miss a few episodes It’s rather like skipping a few chapters in a book. Also modern technology has spoiled me in that I can save up or order a whole series and watch it all at once, my preferred viewing method.