Congratulations on easily killing the hells out of the entire grove without any difficulty whatsoever, you must either be either very experienced, well setup, fortunate enough to come across some things I probably missed or have read a guide in advance.
I had the benefit of none of those things and was shorthanded, for reasons I will get into in a bit
Given how straightforward the goblincide path where all you do is go to positions x, y and z to whack three baddies without much in the way of setup or preamble.. The Evil route is pretty tough by comparison. Heck even the completely optional courtyard fight is easier than the druid grove as you are pretty much handed all of the time and space you need to set the entire area up to your liking
Now as for the point regarding the merchants.
- Never found the Paladins so, I will have to take your word for it.
- The zentarim hideout is locked behind checks, traps and is pretty easy to miss in the first place.
- After the one scene with minthara you are explicitly told not to go back to the camp, so the goblin vendor is out.
- Volo, never freed him from his cage, freeing him didn't seem like the evil thing to do (more on that later as it's pretty relevant to the overall main point here)
- Okay ya got me on the underdark point there as there are two vendors in the colony.
Regarding the payout.
-On the "good" playthrough you get a bunch of sweet weapons, sweet equipment, an absolute trove of stuff to sell off to a very easily and immediately accessible vendor, along with a straight shot into the underdark where even more treasures and such are to be had directly from the goblin camp! On top of all of that a freaking badass druid joins up and hangs out in your camp.
-On the "evil" playthrough you get a few greens (some of which can be acquired on the good run if khaga gets poisoned...) , a lot of grey stuff to loot and sell if you can find a vendor, and a poorly animated sex scene with a woman who immediately tries to murder you! Assuming she doesn't then you get sent through some cursed hellhole (that we don't have access to as far as I know, might be better or worse that the underdark) with a crazy as your guide.
It's a pretty raw deal.
Let's take just a second to talk about companions here.
I ended up losing three different companions in order to follow the "evil" path here.
Wyll, Lae'zell and Gale.
I am now permanently short a wizard, warlock and fighter. This makes the grove fight pretty freaking tough.
-The fighter pulled a knife on me so I talked her into letting me slit her throat, sure there were options to keep her alive but that's not the evil thing to do now is it?
-The wizard attacked shortly after and was unceremoniously stabbed/clubbed to death.
-The warlock dies in the raid.
At this point all I have left have Astarion and Shadowheart who I may just end up sacrificing to the redcap god of fish people because "evil".
Do you know how many folks left/died on the good guy run? NOBODY!!!
I'm not talking about doing one evil questline or a few despicable acts here and there...
THIS IS ABOUT 100% NO HOLDS BARRED EVIL!
Which is just plain counterproductive and stupid on the whole.