why the string function / module change

[Sean 'Shaleh' Perry]

Ok, so I read the what's new.  I understand that for Unicode support the
string module needed help.  No problem.  By why introduce a new syntax that
makes 2.0 incompatible with 1.5?

foo = 'this is a string'
pieces = foo.split()

split(foo) worked just as well.  I understand there were problems making the
string module do this, but still.  Could they have not been _split() or
something to dissuade their use?