You might be right, but honestly it's just a quick vote for 1 character per day (assuming each thread stays for 24 hours)
To make it easier for you, since its 25 characters per poll. Just start with the top 25 from this event and keep excluding 1 character each subsequent thread (unless the top 30 has some big fan faves then just add them in once the top 5 is settled).
I guess the top 1 wouldn't need to be made since this event will cover that. You can start with #2.
At worst, you can revisit this in a few months or something. To actually rank characters, cause this is not much of a ranking. It's a grouping.
Idk I think that would be fun, we'd get characters like Zoro, Law, Rayleigh, then King, Doffy, Kat, Sanji etc. in tight contests for placement. And it would cement where WG ranks these characters at that point in time.
If that still seems like too much, you can honestly just make one for top 10-15 characters.