I think he or she will, something in my heart tells me they are still alive. I don`t think they will reveal their location or who they are, but I do think they will post on this forum in the next 5 years. It is only a matter of time before some big big rogue miners or bitcoin devs do something he or she do not like or see`s a problem with and they will have to come back and have a voice in the matter.
It will probably start by him or her saying something like this.
"Keep using the longest chain" or maybe "use this chain instead from now on"
I did a poll earlier a few months ago I think 19 out of 20 people said they would use whatever satoshi said.
I doubt he/she/they would return. It's kind of like the heroic act of an anonymous person and well he left like that. His name was renown all over the world but he didn't try and bask under that glory. He left the community silently without anyone of us knowing who he/she/they really was. And I doubt that even if he did come back, he/she/they won't give his/her/their voice into matters at hand in that time cause well it's a growing community. He/she/they made it as a type of anonymous transaction without a third party so his/her/their goal was not to make it under his/her/their control or under his/her/ther watch but rather just see what the community can do to build it up from what he/she/they started. And it's going pretty well imo.