Another pointless topic...
Modding community have always been built on devotion with no cash involved.
You want to make money with tweaking without creating anything in the first place?
Just take Unity or UE3 (they are almost free), make your own content, models, textures, scripts, role-play system, etc.
Then, spend some fortune on marketing and many months of production...
Then release your project and keep supporting it for free...
And then, some know-all will say to you if you would give him nice and neat modding tool he will make you some mods/DLC for money. What will you say to that person?
Larian CAN and WILL make their own chargeable content. Why do you think they have to share with you?
And if you think yourself such a great level designer, scripter or fount of wisdom, make your own project, go on the kickstarter and you'll see, how "easy" is this whole procedure of game creation...
The main question to Larian should be why they've promised full modding support and for now we can't even mod the good half of things in normal way. But we are still waiting the answer or even solutions to that question.
You've been given a Great Game and you want to make money while getting pleasure of it with everything ready in the first place?
In Russia, we have a folk proverb:
http://ru.wiktionary.org/wiki/%E8_%F0%FB%E1%EA%F3_%F1%FA%E5%F1%F2%FC,_%E8_%ED%E0_%F5%F3%E9_%F1%E5%F1%F2%FC
(Sorry, no support of Cyrillic, had to make a link if someone is interested).
The closest analog in English is: "You cannot sell the cow and drink the milk".
Think about that.