A question before formulating an opinion…what’s with all the Rumple’s dying/Bobby wants off the show stuff coming from? The current storyline or something read or just speculation?
In reply to your question, here are my thoughts about the fate of Rumplestiltskin. His dark heart could be taken as confirmation that he is going to die. He already had a very close shave with death, until Zelena gave him the elixir to buy him a bit of extra time to track down Isaac. While Rumple may succeed temporarily in getting Isaac to rewrite the villains their happy endings (thereby extending his life for a bit longer), I think Henry is going to become the next Author and set things back to how they were with good triumphing over evil. Also, based on spoilers and what Emma herself already said about wanting to stab Rumple with his dagger, I think after Henry course corrects things so that the odds are again stacked in favor of the heroes, Emma will stab Rumple, kill him, and become the next dark one. That will be the big cliff hanger for S5.
"That’s how you know you’ve really got a home. When you leave it, there’s this feeling that you can’t shake. You just miss it." Neal Cassidy