Originally the last thing I would have wanted was the Death - and in the second movie, no less - but what they're doing is already so far removed from what I wanted at first that I feel a bit more open to unconventional thought. More than a wish it's a theory, because I think there's enough stuff that's pointing towards a "Death" scenario at the moment. It would feel rushed in the context of it only being the 2nd movie, but in and of itself I don't think it's beyond being an effective moment or an interesting story decision.
The main thing I like about it is that it immediately gives Superman an interesting arc in JL: his resurrection, maybe dealing with having no powers at first, telling his loved ones that he's back, etc. It would be his own thing and make his story stand out among all the other plots. Instead of him being the overly powerful guy that has to stand back and let the rest of the JL show off -- which I think is a risk, and occasionally a problem in JL comics or cartoons. Precisely because he's so powerful, he needs a bit of extra effort to be interesting. That's always been an issue with Superman, and I think it needs to be taken into account when writing him as part of a team.