The point about stories is that they should end.... at the end...when we've put work into a complex emotional crescendo - not later, when we're back sniffing like a dog....
Exhibit A: Rose
Lovely moving story of doomed love. Trapped in separate dimensions, he burns up a sun just to say one last goodbye.
(But, then he pops back one season later to offer her a half-human, identical clone-replacement.....so that's nice)
Exhibit B: Martha
She tries to replace Rose in his heart. She fails. She has enough dignity about her to walk away from him and his world, back to her old life, with her head held high.
(One season later, like the ultimate clingy ex, we find that she has joined his old firm and married Rose's ex-boyfriend)
Exhibit C: Amy
She outgrows childhood raggedy pal and chooses the nice, sensible boyfriend. In bizarre twist, her spurned imaginary companion materializes at the wedding to give the union his blessing ....aaah...clever that. You thought the challenge was going to be Daleks and Cybermen, but actually it was all about growing up...
(Next season she's back and finds out thatshe's unwittingly given birth to a glamorous, time-travelling psychopath, whilst a clone made of gooey stuff handles the maternity cover)
Exhibit D: Clara
Talented actress wrestles layered and convincing performance out of the mess that was the previous season. A relationship based on two characters who are never entirely at ease with each other or themselves, climaxes with a nicely judged symbolic hug that ensures that, even there at the end, they don't have to truly look each other in the eye.......
(oh no.... wait a minute......this Christmas she's back, bantering with Santa's elves on a roof )
"As a dog returneth to his vomit, so a fool returneth to his folly".
PLEASE.........LET THEM GO.........