It wouldn't take an entire reworking of anything. A few lines here and there, and maybe a few "I don't deal with your kind" situations. I don't think that would be too complex.
And we are back to one-liner.
Maybe a misunderstanding here. When I say, "A few lines here and there," I mean that it's more than a one-liner. Sure. Zevlor talks to people and says, "Hey. This whatever-he-is just saved the grove. Treat them well." So people will, in general, not reject you at the grove. That's what I'm saying wouldn't take a complete overhaul. You can still talk to people in the grove, buy and sell, etc.
But then, Larian could target additional characters that DO have issues with you. This still wouldn't take a complete overhaul. For specific races, like Drow, Half-Orc maybe, Yuan-ti Pureblood, Goblin, Orc, whatever, there are select individuals who ARE hostile towards them.
So, let's say you're a duergar. You just helped save the grove. Yay! Everyone loves you... except Aron the halfling merchant. As soon as you approach, you get a different dialogue from him. "Well, what have we here? Our GREAT and MIGHTY saviors! Hah! I don't buy it. I know your kind, DARK DWARF! Just keep moving. I'll have nothing to do with you."
Ah, but the tiefling merchant will still sell to you, so you still have a merchant to buy and sell from.
Then, further into the grove, you encounter a dwarf druid. Immediately, he approaches you because you're duergar. "Stop! I don't know what you think you're doing in here, but we don't want your kind here. Get out." You have the choice of leaving or arguing with him. Eventually he might agree to let you stay, but he'll be watching you and maybe even following you.
Come on. They had children and every single freaking person in the grove at one point following animals around. They can have one or two characters who don't trust you following you around because you're of a race they don't approve of. I don't think that'd be a particularly challenging or time consuming thing to implement. A few characters with a few mean dialogues based on your race tag, and some characters maybe trailing you to "make sure you're not doing anything bad" wouldn't break the game - or at least I'd think it wouldn't.
