I really like the idea of more input replacements for other inputs like color and upvar
what I mean is, so we can drag other inputs into those inputs
also, I wish you could see the code for the official blocks and maybe even create a duplicate for your account (not project) to edit it.
we should also be able to make our own kind of block category for our custom blocks instead of being limited to Other.
I also think you should add new blocks like RGBA or hex pen set and maybe some new text operators like "_ contains _?" or decimal to binary and vice versa.
Check out the libraries, which have a lot of what you want. When you say "the code for the official blocks," do you mean the implementation of the primitives in Javascript? Click on the Snap! logo and choose "download sources."
Also, many people make custom blocks and publish links to them so always worth a search of the forum to see if someone has already made a block that your after