Go for 3, no doubts. Here at PM many experts can expand the many pros.

I imagine you are speaking of a website.. take a round on the Dancer website for an almost easy to learn web framework and it's related module Dancer2.

To separate the html from the logic is the first step towards sanity: use Template Toolkit!

Take also a look to PSGI (the protocol) and plack (the implementation) on CPAN, they took the place of CGI.

I have a loooot of links about the matter on my homenode

L*