I understand them not being designed that way but even still imo they were underage. Even in VV besides Kanna, Marie Rose, Koharu, and whoever, they're still reasonably design and at least(although kinda unsettlingly as far as Marie and Kanna) they are legal. Marie and Honoka even if they were made back then, it probably wouldn't have gotten backlash anyway since fighting games from the Japanese almost always have that one underage girl; SC has Talim who is 15 and quite sexualized with how revealing her transparent outfits tend to be, Amy was basically 9-12 during soul calibur 3, 4, and 6, and then Tira, Natsu, and Leixia were all 15-17 during their debuts but sexualized as well too. And Tekken and Street fighter have a few characters where the same thing is applied, but it's how the game carries itself and unfortunately, DOA with Itagaki kinds dug itself into a hole with the bikinis and sexual tones that make it more controversial than the others mentioned since sexual themes wasn't the focus in those other games for the most part, just the occasional fanservice and maybe customization that they introduced over time for everyone.
I really think X2 was what put the nail in the coffin tho, and Itagaki can't deny that either. Now TN is just doing what is successful as far as the Xtreme Venus side of the game and unfortunately the fighting aspect of DOA is taking a back seat because of how DOA6 performed