With hit TV sitcom How I Met Your Mother coming in to its ninth and final season, CBS have officially announced that they have signed off on a spin-off series called How I Met Your Dad. The creators from HIMYM, Carter Bays and Craig Thomas, have both signed on to co-write it with Emily Spivey (Up All Night) and both seem pretty excited by the opportunity to prolong their HIMYM success. The idea is that it will trace the structure of the original series, but this time told from the perspective of a woman with a completely unrelated cast and story. Throughout its run, How I Met Your Mother managed to capture that magical combination of a great ensemble cast and some really entertaining comedic writing. It has won the heart of many a Friends mourner, something which seemed impossible when it first appeared on our screens back in 2005 but has since become one of CBS's major ratings contributors. So it's easy to see why the idea of a spin-off has even been suggested. But how is HIMYM's successor going to live up to the original? Whilst the fact that the creators of HIMYM have jumped on board should provide some continuity in quality, it can't be ignored that spin-off series are always met with a sense of trepidation and usually for some very good reasons. So without further ado, click next to reveal the reasons How I Met Your Father should stay on the ideas pile...