This isn't an online multiplayer game, they don't really need to outbalance exploitive play. Let them focus their effort on something useful, imo.
Balance is just as important in single player games as it is in multiplayer games, if not moreso. Bad balance creates a situation where the difficulty of content can no longer be properly honed in on how you want your players to experience the game. You can see a great example of this in Morrowind. In Morrowind one of the biggest complaints from fans was that the original game was much too easy. By the time you got to the endboss you could just steamroll him without any effort. In response when they made Tribunal and Bloodmoon they cranked up the difficulty a lot, but the result was that a lot of people complained that it was too hard.
Why did that happen? Well, because the game was really unbalanced. In Morrowind Enchantment and Alchemy were so overpowered that anyone who extensively used them became an unstoppable juggernaut, anyone who didn't however would run into serious issues. A lot of the people that minmaxed and optimized their characters while beating the original game were disappointed that it offered no challenge to them, however, when they upped the difficulty of the game to a point where those people would find it challenging the result was that everyone else was now faced with incredibly difficult content, even with the difficulty slider all the way down.
Let's say they made a piece of DLC that was moderately difficult to people with 2000 damage swords, how exactly would someone who "doesn't like it so they don't use it" complete that content? Exactly...