So I started playing around with diffrent wallpapers. It looks like the background of the task bar and folders aren't really translucent at all. They mimic the surrounding colours, so that it looks like it's translucent. Kind of like the way iTunes does for album covers. So if you have a wallpaper that's mostly black and grey in colour. iOS 7 mimics grey. Bright pastelly colours like the ones in iOS 7, it mimics the colours within the area.
As for the parallax effect, I used a pic of a friend of mine as a wall paper, now I can see a little of the effect. It's very, very subtle. Unless your actually looking for it, and looking very hard, you won't notice it at all. I'm a little disappointed. Along with the faster drain on battery, even with background refresh, bluetooth and all other non-essentials turned off. Still drains a little faster than pervious iOS 6. Not bad mind you, but still a little disconcerning. Hopefully Apple will fix these issues in future updates. Just wondering why mine is very subtle, while others, you can clearly see the effect.