As of last night, Apple was signing both 7.1.2 and 8.0, so you could roll back. I'm not sure how long that will go on for though, I'd guess not more than a few days to a week.
I rolled back last night because scrolling stuttered. It's so smooth in 7.1 that I just couldn't justify keeping 8.
Yeah, I had to "flatten" mine and do a fresh install of iOS8. It is snappier, but I would only do it if you're willing to backup first and then totally wipe your unit with no guarantee of a rollback. If you use Siri to dictate emails, I'd go for it. There's tweaking to be done to save your battery. It's all very fiddly and you'll be asked for your password alot. If you have a bluetooth keyboard, link it up to your iPod -you'll thank me later.