A "C" type programming language with no curly brackets (or equivalent) and significant whitespace is a huge negative for me and utter deal breaker. This is the first time I have heard about Nimrod and was very interested to see more. It was all looking so good until I came to this part. Literally I stopped browsing the Nimrod site and closed it down (with some regret) as soon as I saw this.
Is inconsistent. Cause bugs. Can be write like brackets don't exist (http://www.andromeda.com/people/ddyer/topten.html), nullify your argument. Pick the above link and count how much problems are masked with the illusion of the brackets.
Is unnecessary (add noise just to help the parser), and python, haskell and other languages show that could be done better.
From Python-land, if you find that no brackets are meaning it's hard to tell where conditionals & functions end, it's usually a good sign that you're logic is getting too nested.
Yes, it's a pain to work with massively nested logic, but it's actually python's way of saying, "dude! keep your functions small and simple!", which I've come to appreciate.
It's one of the things I like about python, actually, is that it really tries hard to encourage you to write good code. Once things start looking ugly and hard to understand, it usually means that the logic & method you're trying to implement isn't a great choice.