Ok, interesting idea that I hadn't considered before.
As it happens, I've been watching a discussion about a different use for brackets: http://lambda-the-ultimate.org/node/4879. Lots of people (scheme, clojure, this liso guy) seem to have an idea about what to use brackets for, and it's not clear what the best use is for these precious punctuation characters.
I realized that we actually don't need to have a closing bracket to signal the end of the expression. We just need to implement something like the $ operator in haskell.
def (foo a b c)
if $ and
a = 5
b = 10
c = 15
prn "success"
prn "failed"
There should be enough information based off of the indentation to tell how it should be parsed. $ should mean something along the lines of everything indented after the next symbol is a single expression.
You'll like the old discussion on Bullet which had some similar ideas, including considering how to suppress paren-insertion inside such a special operator, etc.
