Is it worth to talk to her if you play as a so-called "good" character?
Generally speaking... not really, as the game stands.
If you've killed the other tow leaders and the fortress is hostile when you go to her, it will simply be combat, but if you go to her before turning the fortress hostile, you will have the opportunity for a conversation. It's a very one-sided and condescending conversation, for the most part, and if you give any inkling that you aren't also completely down for slaughtering everyone in the druid grove in an orgy of blood, then she'll end up going hostile along with everyone else in the room, and potentially the rest of the fortress, depending on various other circumstances.
You can mislead her about the location of the grove, but it doesn't do anything other than give you a chance to escape the conversation safely - you can run back and report her plans to the grove, but the result is simply that she's two minutes behind you regardless, and the assault begins.
She doesn't offer you anything that seems like any kind of a life-line or hope for addressing your parasite, even if you're playing the 'evil' route - just zealotry.
How much do you know of Lolth worshiping Drow? It seems you don't know much as Minthara, before she got tangled up with the Absolute, was a Priestess of Lolth. Drow Priestesses of Lolth are very much of the attitude of controlling everyone below them. Minthara still has that aspect of her personality even after becoming a follower of the Absolute. So it is very much in her character to act in this way. It's either you do as she says or she kills you (or at least tries). The only way to change Minthara's mind on this aspect is to show her that you are more powerful than she.
