I've been meaning to reply to this for a while.
Most of the perl I write has to be backwards compatible to early 4.0 era versions of perl. Also, the code needs to be able to run on every unix platform we support.
So its just not feasible to use CPAN modules for everything, becasue garanteed, it'll break somewhere.
Coincidentaly, thats why I also have to write in pure sh shell....