I really think (and hope) that all our main rebels in the new Rogue One movie should die.
1. Would give the movie extreme weight, not found in any of the other movies.
2. Makes continuity make sense. One of the main issues doing prequels is that continuity is always difficult. To me, you have these crazy effective operatives... yet make no appearance on the assault of the Death Star? Where were they on the Hoth base? Why weren't these people picked to attack the base on the forest moon of Endor? But if they die... it wraps it up nicely. We obviously have force sensitive individuals in this movie, if not outright Jedi. Why wouldn't Luke seek them out... why would Obi Wan and Yoda gather ALL the remaining Jedi? Because the ones they (the rebels as well) know about are dead or scattered.
3. With Star Wars: Rebels they have already nerfed the Empire enough. If you have watched that show, you know the Empire is basically a bunch of bumbling idiots who can't do anything right (at least as of Season 1, I admit I am a little behind). We need to see an Empire that can get stuff done. Earn the fear they have in the galaxy come Episode 4. Yeah, the plans get out...but the rebels need to be dead. Maybe one makes it out with the plans... the rest dead or captured. If we continue with this weak show for the Empire it totally invalidates any of the fear we felt through the original trilogy.
(Also common misunderstanding is "Many bothans died to bring us this information" ... that was from Return of the Jedi regarding the SECOND Death Star.)