I don't think something like the 1712 would be a huge step up from what you have, if at all, with the exception of some newer features and MultiEQ XT. A sub would likely be a much bigger benefit.
For the Roku, unless you get the XS (current models) or the top model 1st generation, they are all wireless only. Which really just means you would need the top model that costs you a little more, or accept wireless. Regardless of that, I'd run the ethernet.
I have a Roku2 XD and it performs mostly well, just with certain channels it tends to freeze randomly, which gets annoying. Other than that, it works fine.