Ok so now it's clear that the "evil" path means...
...using the tadpole to gain more power. Allying yourself with this evil faction you know nothing about that is trying to kill you.
Litteraly everyone in this game is trying to kill you ... some need to check some conditions ...
But Minthara, Ragzlin, Gut, Crusher, Shadowheart, Astarion, Ethel, Kagha, Zevlor, Nettie, Halsin ... they all try to kill you, some sooner, some later ... and i bet this list is not even complete yet.
Motivation is the most important thing in writing evil characters. If I play evil it's an intelligent, methodical evil that has a goal. That goal can be personal power, but I wouldn't ally myself with whatever evil faction comes along or keep such a meaningless power source knowing it can kill you. Furthermore, the goblins and the other weak-willed misguided individuals don't exactly scream "join us". I'd rather ally with the Zhentarim who are an established faction with smart people.
Not necesarily, usualy yes, but certainly not allways ... and it makes me sad to see how many people here is so black and white ...
Having a shadow magic infused tadpole in your head and being a part of someone else's unknown plan means you are not in control. The first thing a sensible evil character would do is get back in control. Besides, a slimy parasite in your brain that is largely unknown is simply gross. And you know it wants to kill you. Say the creator of the shadow magic decides to kill you. They can just dispel it and you die a horrible death and turn into a Mind Flayer. Getting the tadpole out is the only sensible thing anyone would do. And also the perfect motivation to do evil things. But this is not even an option in BG3. I would totally wipe out the Tieflings if the Shadow Druids would remove the tadpole in return. Getting cool powers seems more like it's for gameplay reasons to get more Bonus Actions and doesn't outweigh the fact that you can be killed or controlled by the shadow magic tadpole.
What do you mean not even an option ... whole story is just about doing precisely this.
Yes, you didnt yet come to and end ... since when does that mean that there is nothing happening? O_o
So my evil Drow Warlock ended up killing the other evil characters for Halsin because he seemed like the best or only option to remove the tadpole. I was really annoyed this didn't happen. And the parasite is gross, I just want it out regardless of whatever.
And its perfectly possible ... i dont see your point here. O_o
Yeah, I'm not sure what the "evil" path is even about. When I went to the Goblin camp and it was presented to me, my first thought was "Why? Why is this a choice? Why would I do this?"
Why is this a choice ... so anyone who DO have reason, could do it ... that should be obvious. O_o
Why would i do this ... if you have to ask, you probably should not ... simple as that.
It's like the evil character is meant to be stupid or just do things for no reason.
If you want to play them as such ... you should have that option.
Also the fact that your current character dont see any reason to do *something*, does not mean that
no one ever had any reason to do exactly the same thing ... its just about thinking outside your box ... after all is a
Role-playing game ...
Sad to read trough this forum and see how many people cant do that.

IMO, better evil dilemmas would Auntie Ethel giving power or knowledge for eliminating the brothers. Kagha offering their magic to limit the ceremorophisis process and giving more chances to use its power without transforming in exchange for eliminating the Teiflings or forcing them out, knowing it's likely their deaths.
Oh please, Ether can (and will with some dialogue choices) kill both those peasants with snap of her fingers ... why should she give you anything for that?

Kagha should kill you the second she find out what is in your head.
Give me, the player, some gameplay bonuses and the PC some powers like more abilities or the ability to use the worm more without consequence to the PC in exchange for doing "evil" things.
You cant be serious here.

You can even layer choices. Kagha offers some powers or influence throughout the rest of the game for some evil act. You do the act and find she lied or used you, you then get the option to use the Goblins to wipe out the Grove for revenge and to show that you shouldn't be used or mislead.
You allready can use goblins to wipe out the groove ...
In the Goblin camp you're able to kill these absolute people, why not give the PC the ability to fight them and then force them to obey you instead. Hell, for the scenes with characters like Minthara they could make it an abuse of the characters power and position instead.
I presume it have something to do with the fact that Knockout is still kinda useless ...
Maybe im wrong here, but in your camp there is cage ... and when you choose bounty hunter specialisation for your ranger ... there is specificly told that people restrained by you will have harder escape ... so i dare to presume that there will be some option to take people to custody.
Edit: In Fallout 2 I could play all the families, gain their trust and use them, then sell them out to the next family. I could bone the Bishop family leader's wife and daughter. Those are more evil choices that to me make sense.
Its just another option ... not the only right way.
Shadow Druids, same thing. "Do this for us just because". No motivation for getting rid of the tieflings related to what is driving the player at the moment.
I know about single shadow druid only ... and its Kagha ...
She never told me to "do this for us just because" ... more like "do this if you wish to help them(notice them, not us), or get out of my sight, i dont have a time for you, nor i care about what do you want".
A good character would never use it, they'd want to get rid of it at all costs, even to their detriment at times.
An evil character would think how they can get rid of it, but would also consider how it could be used for their gain.
Good character can use it, maybe not lawfull good character, bcs they would see it as some kind of stain ...
But for example Wyll is good (kinda selfish, but in general he wants to help others ... therefore he is good) ... yet he made his deal with Fiend ... is that so different from tadpole? After all, ends justify the means.

Evil - Requires slaves, power and material goods as reward, not interested in colateral damage incurred or methods used to obtain cure. Torture, theft, murder....preferable. No reward? Bye bye. Ends justify MY means.
This is the problem ... you are thinking as player, not as character ...
Or you are simply another black/white judge who see only his way as the righ one, and everyone else are siply wrong ... or stupid ... or both ...
Sadly, world is a little bit more complex. :-/
I wonder what reward you think those goblin kids had to throw rocks at Halsin in his bear form.
stabbing Nettie with that bloody branch of thorns and torturing an answer out of her with a promise of antidote. The cow...
Nice idea ... i like this! :3
Or offering the dark Druid to dispose of her Tiefling issue in return for help, luring the Tiefling a out and then letting them get massacred by the goblins, potentially stabbing the goblins in the back afterwards to make sure they don’t present a threat down the line.
This would be a bit problematic ... i need to try sometimes to kill Halsin and then kill goblin leaders so i see what will happen ... but so far it seems like groove concidering goblins to "no longer present a threat" only when he returns ...
Otherwise, its interesting idea ... yet, im not sure if Minthara would agree with killing only bunch of tieflings, and letting druids to live happily ever after. :-/
Obviously I know now, but the story should make sense the first time you play it.
And it does not? O_o