A great question someone on reddit asked and I couldn't find a good answer. Well, other than to support the testing (and apparently a spicy scene for those that finish a certain mission). I think a great point of discussion here is the goblin vs. tiefling decision. Spoilers after this point
To set the stage my 'evil' journey started with my half-drow warlock, which the dialogues recognized when it made sense, so I had what at least felt like an advantage when conversing with the 'evil' crew.
When I first encounter the goblin army, I have no choice but to fight them, which automatically puts a bad taste in my mouth because they tried to kill me. Then even if I ignore my vengeful desires and free their friend, a group still attacks me. That encounter is okay since it is just infighting that I would imagine happens in most goblin camps. Then when I finally get to meet the leaders they are all accusatory and want to kill me unless I pass a series of checks that aren't required from the tiefling side of the mission. I feel like it is extremely hard to justify wanting to join them when they have offered me nothing other than violence and mistrust. They don't even have an offer to help with the tadpole, unlike the druids.
I think this can be fixed with an extra encounter before getting to the grove that provides us the option to help 'scout' the grove. Maybe the Drow, who we know watched us fall from the ship, sends a minion with an offer: Help her and she will teach us how to unlock the secrets of the tadpole. She has sent a group of her most useless fodder to test the defenses of the grove, and wants you to 'help' the grove to get inside as a double-agent and free her scout. If we make that agreement, we can still choose to betray her later, but at least in the beginning we have a reason to join. The promise of power is a strong motivator for the evil character of all flavors.
This can then ripple through the other encounters. A little more trust from some of the leaders. Maybe a challenge to a duel by an aggressive goblin trying to prove he should help lead the raid instead of you. The opportunity to pit the leaders against each other is always nice, especially if we are already friends with the Zhent and the Drow. Maybe they want an excuse to get rid of the hobgoblin because he is making bad business decisions, and want to install themselves as the leader.
I think there are a lot of opportunities here. Let's make Faerûn evil again!
p.s. Please don't tell my Paladin I said that.
