This one is easy to change in USER PREFERENCES > THEMES > USER INTERFACE > MENU BACK. – Just turn the aplha value A to 1 to make the menu fully opaque.
Although I like the transparency effect as well, I might agree, that it looks less cluttererd and is easier to read without it. I wouldn´t change the colors though, I think it works well with 100% opacity and the dark grey background.
I agree on the benefit of the icons, once you get used to them they are actually great help in locating a specific item faster.