This is totally a must-have, since it allows to block whole layout elements instead of just ads (like DeviantArt's ad column - giving an extra column for page content)
"Block custom elements, like in NoAds"
You're goddamn right! I need such a thing. If you can make adblock to not download elements that I blocked, not just hide, that would be great.
It is a good idea to replicate functionality of Firefox' ABP, including Element Hiding, built-in tool to select elements to hide and support of such entries in updated lists. Without that, the functionality is not complete.