I think it is important to differentiate between HAML syntax and SASS. Even though both are part of the same package, SASS syntax is actually quite minimal and closely follows CSS syntax, without the extraneous syntactical elements like curly braces etc.
Chris Eppstein, the inventor of SASS has stated elsewhere that one of his primary goals is to make SASS friendly for designers to use, and he claims to have sought feedback from designers as well. See comments here : http://jeffcroft.com/blog/2009/may/20/applying-oop-concepts-...