People who want to go the evil path with her still can if we have a good option to save her, you don't lose anything. Who cares if other can recruit her on a good path, you play evil because you like to play evil, not for the exclusivity. This is some weird gate keeping. More meaningful choices would mean to either join Minthara to raid or to save her in a way which doesn't include being a murderhobo.
Pretty much was going to say all of this.
I just don't get people who want to deny others some enjoyment because they'd rather enjoy things their way. It's like people who are asking for a happy ending for Karlach, but other people chime in that they prefer her current endings for any number of reasons.
So what? How does having more options suddenly make your preferred options less in anyway?
No one is asking to remove what's in the game now. Adding a "good guy" option to Minthara does not impact an evil playthrough at all.
I suspect people are looking at this as a zero sum problem, that adding to the game means something is removed. Or that it will somehow diminish their choices. That's not really the case though. One thing that would make a good compromise here? Make the "good guy" Minthara recruitment extra difficult, which it should be given the circumstances. It will add value to evil playthroughs since Minthara's recruitment would be significantly easier, but still give other players options if they want to go the extra mile for them. That's what people are asking for after all, an option, something more, which will only make the game better. No one is trying to take away from your game here.
You described it perfectly, I like the example with Karlach! Imagine saying you don't want others to have a happy ending for her because you prefer the sad one. Can you imagine telling a Karlach fan to just don't recruit her if you don't like her ending. And by knowing her situation, your choice of recruiting Karlach should have consequences?
I did recruit Minthara in my first playthrough, I LOVED Minthara even more after getting to know her, but hated the act1 decision I had to make to get her. Originally I planned to get the game a second time on console because I prefer to play on that platform, but since I have to rely on a mod to recruit her on a good playthrough ( thank you Rukongai ),I don't have that option on console and therefore I don't have any intention right now to play BG3 again because I don't want to play this long journey without my favourite character (like a Karlach fan would not want to play without Karlach, or even worse being forced to kill her).
Minthara and Halsin could have really interesting banter, Shadowheart and Lae zel managed to share a camp after some "confrontations" as well.