To bring this thread back from a Python vs Perl flame-fest, to the original concept "is mandatory code indentation to show structure a good thing, and how can we do this in perl", here is my view:
I indent my code to make it easy for me to see the structure and purpose of the code. How the language compiler / interpreter / parser determines where a code block starts and ends is its own personal business, provided it interprets code structure as I intended it to be.
At the moment, I am coding far more in C and VB.Net than perl. (Yeah, sometimes life sucks.) I probably tend to overuse curly braces, but that way I know there is no confusion - either for the compiler or myself. But I will also break up long lines, particularly for functions calls, and line up parameters.
My bottom line - we doan need no steekin mandatory indentation. It should go the way of column 72 being the line continuation field, and mandatory line numbering in columns 1 to 5 (with column 6 to indicate a comment).