Well here's where I'd disagree and of course this is just me spitballing and what I'd do if i were writing it.
It's pretty clear they're going with Superman as a messianic figure, more so than the initial Moses parable he started out as. So his "death" at 33, if executed properly, can be used as a narrative device in the same way that the martian manhunter stepping away from the justice league was in the cartoon. Snyder has spoken on this so I think there's truth to it, but this universe's version of superman is still finding his way and trying to become the guy he "traditionally" is. Rather than have this immediate connection with humanity, a humanity that at times fears him, ostracizes him, and feels like he doesn't belong here because he's an alien, this death and his sacrifice is a way of him deciding that humanity is worth saving despite all the BS he has to deal with.
Whether that's executed properly or even the beginnings of it executed properly is a different discussion entirely and I'm sure someone will have it, but the idea of him giving his life for a cause and then coming back as a new man with a new outlook and a stronger, more confident character, I'm all for that. That would actually be a better reason and narrative than the reason they killed him in the comics which was just to sell books and they got tired of writing him and wanted to put him on the shelf for a while