The problems for me are:
1) you can bring back characters from the dead, sure, but you can only do it a few times in a story and have a very solid and logic reason for them actually escaping death and coming back.
2) I don't think Oda will make any kind of relevant subplot for Robin due to Saul, I mean they will have a touching reunion and some new infos, maybe, from Saul but nothing more and that is because Robin (like almost every other SHs after the time skip) barely gets any panel time and even less focus and dialogues anymore. So her getting a subplot is very unlikely. I'm still waiting to see Zoro go to Ryuma grave or actually confront the smith dude in Wano about swords and sword smithing.