I agree. To simply kill off Batman is a bit of a "get-out-of-jail card". Why deal with a complicated ending of Bruce simply retiring from the cowl or continuing as the caped crusader when you can just kill him and show shots of mourning Gothamites and supporting characters?
These same Bane fans who also predict Batman's death at the end of the film may want to re-watch The Warrior to see a good example of victory through perseverence and camaraderie, rather than death.
More than anything, Bane is a plot device used to bring Batman back to his purist roots of shaking Gotham out of apathy and inspiring its people. Bane killing Batman or driving him into sacrifice just doesn't make sense because, unlike the other villains that challenge Bruce's ability to be Batman, Bane is created to challenge Bruce's ability to persevere past the cowl and into regular life.
I think people want Batman to die because they think it will create a definitive moment in this trilogy unparalelled by other superhero films or comics. They forget, though, that this trilogy has already been filled with iconic events and characters, and to kill off Batman is to ditch an even better, more symbolic resolution: Bruce realizing himself.