I agree that Rockstar shouldn't have left those resources in the game, but any malicious modder can really hurt a company PR-wise. Even just allowing people to mod dialogs, might have a person with bad intent add slanderous, pornographic, violent, racist, and what-not text in the game.
Not much people will do that, I agree, but the slightest chance of it allowing to happen might be a decisive factor for many developers to disallow modding.
It might be free publicity, but such publicity is always bad publicity for a game, with the best case scenario being that the ratings bar is pulled up (massively decreasing your target public), and the worst case scenario your game being pulled from the shelves.
Either scenario is bad, especially for a small company such as Larian Studios.
Don't get me wrong; I personally prefer to have modding capabilities in games, because I'm also one of the many who likes changing the game more than playing it. But I can understand if any developing studio decides not to do it.
Disclaimer: Please note that this post does not reflect any decisions made for D2. I'm not saying modding will be able in D2, nor am I saying that it won't be. You'll just have to wait for more information on this from someone who has the authority to give it. Sorry about that.
