Indeed you will have to re-install all your non-core modules. It happens everytime there is a major upgrade: I had to do it when I switched from the 5.6 to 5.8 series.
It is less of a burden than it seems: by installing MinGW you get yourself a compiler which is compatible with AS Perl and then CPAN can install most of the modules by itself (after making first a snapshot bundle of your existing modules). The few which refuse to be installed by CPAN I download with ppm.
A program should be light and agile, its subroutines connected like a string of pearls. The spirit and intent of the program should be retained throughout. There should be neither too little or too much, neither needless loops nor useless variables, neither lack of structure nor overwhelming rigidity." - The Tao of Programming, 4.1 - Geoffrey James