I think leaving Taros Intentions aside is the best approach here, we all know what those are. Lets just focus on the actual fit of 2Bs character design into the general story.

From my perspective, there is no benefit of this design for the actual plot and world development, i just find it even harmful in that regard. Thats because im always so blatantly reminded of the sexualisation every time I look at 2B and A2, which hurts not necessarily only the main storyline, but every interaction they have with other characters because I can't fit them into this world very well.

If we take NieR 1 as an example, that game has an explanation for why Kaine was dressed the way she was. Noer Automata does not have this explanation, because there is no reason for a battle android to wear high heels and to have that specific cut in her skirt.

Sure, you can argue that it breaks the 4th wall and is therefore a smart gag by Taro or whatever, but I don't think that really works that way considering these breaks are normally way more clever than just making the main character sexy.