I think Han dying early in ROTJ would have undermined the importance of Leia rescuing him from Jabba, but I think I could have accepted his death during the siege on the DSII. At the time though knowing there were no more sequels coming having him survive worked fine (happy ending with him and Leia).
Knowing we have 2 full films following episode 7 I think there's a different reason for killing him off now. We don't need to see Han go off into the sunset...again.
In my scenario Han Leia and Luke would all be the leads in e7, with the leads in 8 and 9 playing bit roles. Again, I'd put Han's death in at the very conclusion of e7 so Han would still get a chance at a last hurrah, his death would have to be dramatic, sacrificial, brave.
Then by 8 and 9 Luke would have the bit part like obiwan. This way it's a compromise with Ot fans to give them a final act but allow 8 and 9 to belong to the new generation.
In the end it really depends on how the writers would end up doing it.
With hindsight, can we imagine ESB and ROTJ had they not killed off Obi-Wan? Or Twin Towers and ROTK with Boromir alive?
Character deaths have to serve a purpose of course, my suggestion of killing Han (and possibly Leia) require that their deaths are done right. Not just for shock value or something.
I can understand the marketing value of Han being in all 3 films, but in the end, if he's there to serve no real purpose other than to draw 50 year olds to the theater in 2020 then that's pandering and not real storytelling.
