I agree that most of the stuff that's in POSIX should be either in the core or in some saner named modules. This module makes no sense whatsoever.

The $array[i][j+1] looks good only as long as you use single letter indexes. What would $array[length] mean? $array[$length] or $array[length($_)]?

Because one is block and the other is expression. Just use if(){}!

Well, I would agree that if ++ is magical, -- should be as well. I do not see the need for a separate operator/function though.

That would be way more confusing. If you write foo(...) anywhere within an expression, everyone except those coming from functional languages with support for currying will expect that function to receive as parameter(s) the stuff in braces and only that stuff in braces.