I'm not a "veteran" of romance dramas but the first thing this love triangle reminded me of was Madoka Magica.
Hitomi/Aki: "If you don't attack, then I will!"
This is either the kick in the ass Himari needs to actually become lovers with Yori, or she's going to fucking lose. Of course the latter probably isn't going to happen because most romance stories are just not written that way, but like many other people here I'd be fine if Yori and Aki become lovers and Himari fucking loses if she can't figure it out. Worst-case scenario, Yori rejects Aki, Himari never figures it out and just stays friends "forever" with Yori.