I just think that the customization of the custom blocks is limited, so why not expand it A LOT more?
(Sorry for the huge image, please spare me)

Yes, I think this would be near impossible. But it's doable though, come on! DO IT!
(Also yes, report will be a new block.)

This is a good suggestion, and good mockups! However, many of these have been suggested before

Being able to make your own dropdown inputs: http://scratch.mit.edu/discuss/topic/18928/
Being able to return a value from a custom block: http://scratch.mit.edu/discuss/topic/20661
Making custom c and hat blocks: http://scratch.mit.edu/discuss/topic/69132/