I get what you're saying, but why even bring Palpatine back? They potentially opened an issue that was already closed and in no way needed reintroduced. So now we're going to get a super predictable scene where a mentee turns on his mentor AGAIN? Wow. Haven't seen that before. At least Rey would be something different (or maybe not - let's see if they don't force some meaningful parentage on her after all...)
This is the small world problem. All this forced connectivity is potentially (again in fairness, we'll see...) squeezing the story into the same molds all over again.
Let me be clear here. I'm not happy that Palpatine is coming back. I find it completely ridiculous and there is a very good chance that bringing him back will retroactively ruin the entire Saga, at least for me.
How they handle this return will be extremely important to decide that. If they bring him back in the ways that will completely negate anything the Skywalker family bloodline has done in the previous 8 movies I will be livid. If they bring him back how it looks like they are i'll be pleasantly happy IF they can come up with a reasonable explanation of how he is still alive.
We're calling these nine episodes the Skywalker Saga because it has been a story told with that family at its center. The Skywalker's are intertwined with Palpatine so it makes sense to bring him back for him to be the ultimate enemy as he has been for the Original Trilogy and the Prequel Trilogy. As it's been mentioned, I don't believe that Palpatine was the plan all along as Abrams wants to pretend but it's what we were left with after The Last Jedi. There weren't many loose ends to play off of.
What other scenario would we like to see in the final movie? Introducing a new villain? Kylo Ren being the big bad guy after he's failed the first two movies? Etc? No thank you. Palpatine just makes sense IMO. Could things have been planned better from the beginning? Of course but with where we are now I think it's the best option left assuming they do it properly.
"It's like poetry, they rhyme."
I do think they're going to bring back Rey's parentage for it to play a role, I don't know who it will be but I don't think it'll be that she's a Skywalker. For that reason I don't want her to be the one to finish off Palpatine knowing that they're referring to this as the Skywalker Saga. It just doesn't seem right even if we get the Mentor/mentee situation again I would rather see that than some random new character be the one to finish off Palpatine leaving the Skywalker family basically pointless and failures besides training Rey.