Rukia was definitely the heroine up till 181. That is irrefutable, well unless you don't think KT has heroines, but let's just abandon that constraint for now. After 181 is where it gets a bit muddled up, but I still think that Rukia ends up retaining her heroine status.
Anyway, I definitely have a hard time disliking female characters. I liked Fllay Allstar from Gundam Seed when everyone thought she was a complete manipulative bitch, and she was initially, but she grew out of that and turned into a much more sympathetic character. I liked Shirley from Code Geass, despite everyone thinking she's a carbon copy of Orihime. I even liked Mitsuki from KGnE, and that's a hard character to understand and empathize with. But somehow, KT's portrayal of Orihime just makes me so frustrated and annoyed. I only dislike one other female manga/anime character so strongly, and that's Lacus Clyne, but it's mostly because she's Kira's plot hax. But even Lacus is a much stronger character than Orihime when I think about it, cause she can actually accomplish things.
I just can't see anything deep in KT's portrayal of Orihime as to define her as a heroine, and I believe if we compare her to Rukia she falls extremely short. Yes, Orihime's role did increase significantly in terms of panel time, but she hasn't shown herself to be worthy of heroine status.
And this is just textual analysis, not including the numerous JUMP covers with Rukia, color spreads, merchandising, the SOULs and VIBEs covers referring to Ichigo as the Sun and Rukia as the moon, and of course popularity polls.
If Rukia was considered the heroine of the SS arc, then Orihime should "technically" be considered as the heroine of the HM arc. But she hasn't done anything remarkable as for her to stand out against Rukia at any point of time, and if KT designed to switch heroines, he knows Orihime would have to compete with all that time dedicated to Rukia's development as a character.
But, even after 70 + chapters, I still can't see anything defining Orihime as a character growing stronger. She's been inconsistent and all over the place and spent the last 30 chapters just shouting "Kurosaki-kun". Furthermore, she kind of forgot about her idea to reject the hougyoku and choose to stay behind willingly. I thought she was supposed to show amazing resolve concerning that, but we didn't hear any sort of protest from her once when Ichigo was like "let's get out of here" right before the Nnoi attack. After the Kenpachi fight she also acquiesced to go home. - I don't blame her for wanting to go home, but if that was supposed to be important, she missed her chance to be heroic and choose her own path. Instead she ended up being forcibly brought back by Stark.
She sat on the sidelines and ended up being used a sexual joke with Grimmjow dragging her, bound, chained, and gagged. She got NNoi's fingers put into her mouth. Aizen was almost seducing her. Orihime barely had any dignity in her captivity.
She listened to everything "Kurosaki-kun" said, even healing Grimmjow so that Ichigo could feed his ego in having beaten Grimmjow Jeagerjaques at full strength. She was able to have the courage to protest against Grimmjow when he told her to heal Ichigo so that he could fight him, but not the courage to refuse Ichigo's stupidity.
And as for showing actual emotional support to Ichigo, she got scared of the vaizard mask and made him feel insecure, and then she lamely cheered him on, everyone agrees on that. What did she say "I don't care if you don't win, just don't get hurt"? Either way it was kind of irrational since if he didn't win, he would die right?

She did heal him and save him from dying, but yeah so did Hanatarou after the Renji fight and Yoruichi after the Kenpachi fight.
Rukia's performance in the HM arc was definitely more heroic despite limited panel time, and despite her being significantly underutilized, aka being left to bleed on the floor for almost 40 chapters.

She was the only non-captain to kill an espada.

And she emphasized several times how much she wanted to save Orihime, even crawling on the floor till she collapsed.
Not to mention she was extremely focused on Orihime almost throughout the entire arc, with even the last chapter.
Tbh, if we're to believe Aizen that Orihime's purpose lay in being bait, then I think a lot of things make sense with her characterization and she can become decentralized.
So yeah, Rukia for life! For life!