Looking at my old Robin comics, more specifically, the one featuring Stephanie's funeral (Robin #132), I noticed something quite interesting, i can't find the scan online but on page 5/6 it shows Tim and Bruce and talking and DC made sure the part where the priest says "in hope of her return and resurrection". 
DC made it very clear that that part is to be shown. 
so do you think that DC planned Steph's "resurrection" from the start?

they normally decide to bring back characters that have died
No one is ever really dead in Comics its just a matter of time til they come back

Anytime you kill a character off, especially in the comic book world, there's always the option of bringing a character back, even if it ins't planned for them to come back anytime soon, a writer could simply say "Hey, let's bring back so and so!" and they just find a way to loophole that character's death.