Why play evil?
Well. firstly, I like to address that I do not play to what's good or evil.
"Not only did she assassinate the Lord, that would be too quick. Before that, the Lord had to suffer. So, the assassin snuck through the castle, finding all his sons... slitting their throats one by one, and gutting them like wild pigs. One after the other they fell, and even yet, the assassin wasn't finished. She made sure to collect a piece of each one - and gathered the pieces in the Castle's kitchen. There, she would prepare a hideous dish with them all. Disguised as a servant, she took this horrendous pie filled with boy's fingers and men's toes to the Throne room. As the lord of the castle excitedly expected his most fine meal, he quickly became mortified as he looked straight into the unliving eyes of his eldest son on his plate - He gasped for air, as he felt a knife on his throat..... "Ordinarily, this Assassin would be considered pure evil, right? Yeah. But it's fine if Arya Stark does it out of vengeance.
Context matters, and even when I go the Heroic route, I'm not above going medieval on my enemies, either. As the Klingons say; revenge is a dish best served cold.
The Dark Urge I'm really excited about playing the Dark Urge. Because, we all have evil urges - it's our ability to control them that makes us civilized. Have you never fantasized about beating the everlasting crap out of that guy that stole your girl away? Have you never lost yourself in a fight and taken it too far? Now, what if that Urge becomes too strong to resist? Regardless of what the source of this Urge is, once you know you have it, and you know it needs a release, where and when do you apply it? Can you resist it long enough before it needs a resist?
I *love* this sort of story, and I cannot applaud Larian more for letting us experience that. You're playing evil, without having to play an evil character. The evil in you becomes just another obstacle that you need to deal with one way or another. You end up directing that evil as best you can; hoping to retain some semblence of who you are - or, perhaps you realize the futility in that, and just roll with it. I can't wait for this. Perhaps you reach a point where you think; this far and no further and have to destroy yourself to save the world. Or something. Anxious to see how this can play out.
Playing a simpler evil. I don't like playing the Lawful Stupid Paladin, but I don't like the wanton-slaugher Chaotic Evil monster, either. Both are just dumb and shallow. But. I do like the concept of a selfish character. You're not an adventurer, you're just someone that doesn't like your circumstances and will do whatever it takes to change them for the better. You might do something Altrustic, but only if it serves your purpose. And, that outlook rapidly turns into a quest for power. And power, is relative. So you ensure that those around you, never exceed you or get in the way of your goals. And, power can mean a number of things; but all of them mean you can influence the lives of those around you - to further your own power.
...the evil path, some planning to commit terrible acts of evil like killing all the druids for instance.
Yeah, I kind of think Larian has dropped the ball here. I think the 'good and evil' routes should have costs and benefits. I think that the 'evil' route should include a promise of something greater; because there is no incentive to join a bunch of dumbass Gobbos over Druids. They offer the same thing, the same answers. Perhaps a slightly more pragmatic approach to find the Absolute. Like I said above, I don't pick evil for evil's sake, but some of my more nefarious characters might take up Minthara's quest and kill them all for the right incentive.
..And, because I want to experience that side of the story, at some point I'll rationalize that decision from a more meta-gaming perspective.