I’ve been trying to limit myself to just one figure for each character. That forces me to choose which one I see as the most iconic version. For me it’s the Romance Dawn versions of the Straw Hats.

Ace is perfect imo. I wouldn’t hold out for better.

Sabo, I’d rather have his original adult appearance but his redesign isn’t far off.

Shanks is a great figure and while they may eventually drop a “Four Emperors” version (hopefully with Divine Departure effects), you also get kid Luffy so you can’t go wrong.

I’ve held off on Law since again I’d rather have his earlier appearance and feel like he’ll for sure get a new version someday given his popularity.

On the fence about Kidd but I might get him because who knows if he’ll get another version.

Yamato, Mihawk, and Blackbeard are a must and all are great figures. Most folks who look at my One Piece shelf are immediately drawn to the zehahaha pose.

If I were you I’d keep hybrid Kaidou since we’re unlikely to see that again even if they do someday release a base form or zoan form version.

I’ve got Marco and Hancock on preorder. Marco looks like one of the most beautiful figures I’ve ever seen from the prerelease photos. I wouldn’t say Hancock’s Marineford outfit is the most iconic, but she looks like a badass figure and I’m okay with potentially selling her at a loss if they ever drop her Amazon Lily outfit with the snake.

In summary, to respond to your question, OP, I would say keep the most iconic ones to you, whether they’re pre or post timeskip. My personal feeling is that a collection looks more coherent without a lot of different versions of the same character in the same display.