As someone who doesn't own the game, but is ravenously consuming BG3 content on youtube, I only recently saw the change and wanted to say I prefer the old look. I did mistake Minthara for a male when I first saw her new look.
To me, the old hair conveys that Minthara is driven yet cunning. The unkempt hair combined with her co-operation with goblins, shows she isn't concerned with prettying herself and is more focused on achieving her goals. This hair covers the sides and the back of her head, which gives the impression that she's hiding more of herself. The 5th patch hair makes Minthara look more aggressive and straightforwardly evil, because it is shorter and sharper.
I was looking at both pictures while playing through her voice lines, and I think her voice matches better with the new short hair. However, combined they make her seem so comically over-the-top evil that I could actually imagine her wearing a 40k commisar uniform. If you pair her voice with her old hair, I think the player will be surprised with the contrast between the softer look of her hair and her ruthless voice lines, which could emphasise her deceptiveness. This contrast might also tempt more people into romance because of "gap moe".
That said, I haven't seen any videos that showcase her cunning, apart from the romance. I also noticed some people who enjoy her new hairstyle more, and I think if any female character were to wear short hair, a drow is a good candidate. Alternatively, you could give it to a female fighter, with examples like Casca from Berserk or Cassandra from Dragon Age: Inquisition. There's just something about Minthara's current look doesn't sit well with me, maybe remove her bangs or something?
