extending core controller is worth design solution in codeigniter 2.0 ?

[eluser]Ravi Raj[/eluser]
Hi Guys,

Just go thorough following article http://philsturgeon.co.uk/blog/2010/02/C...ing-it-DRY

My Question is that is it good oops design approach? should not we create separate package or driver to distinguished application logic like user group ACL or front-end APIs to render page ?

confused little bit with Phil approach. can anyone have better idea about it ?