Please do the move to complex_repr if everything then works the same (i.e. nothing breaks the build) if the readability is in fact improved. Also, change the docs and fix the tests. You know the drill.

P.S.: (1+2j) is worth changing to become (1 + 2j) in the future (in Python 3.3 if not sooner?). Is it very hard to do this? It's worth changing this. Reasons like 'Readability counts.' come into mind...