I guess you are misunderstanding my point, but that isn't surprising.
The "how" is irrelevant.
People were theorising it would be through Hiyori, through Marco, through Chopper, etc.
It never actually mattered "how" Zoro came back, what mattered is that he *would* come back.
The whole "double the pain" thing could have been added to any solution that was found to bring back Zoro.
Whether you find the way Zoro comes back bullshit or not, at the end of the day, it doesn't matter.
If Zoro comes back through the Grim Reaper, through Marco, etc...
It would simply be Oda's way to get from A to B.
Also, an FYI, I am not a Zoro fan.