Shanks especially for emotional/personal reasons and decades of influence and importance but all 3 emperors have extremely important relevancy, hyped, importance etc in their own ways ofc.
I genuinely can't decide which option is the best but Shanks has been there from day 1 and has the most importance due to Luffy and Usopp, so he takes it for me regardless tbf.
I really hope all 3 get done justice though somehow. Especially Mihawk and Crocodile but some of BBs crew and Kuzan too. As well as Shanks, Buggy and Blackbeard ofc.