According to CD Projeckt RED, The Witcher 3 will be supported for years to come and will have free DLC on the PC. In an interview with RPS, CD Project head Marcin Iwinksi had this to say when asked about The Witcher 3 DLC:
"It's too early to talk specifics, but definitely all the DLCs and updates will be free. Of course, we'll see what the platform holders will allow – what we can do for free [on next-gen consoles]. I mean, there are different business models on consoles. From our standpoint, we'll definitely do everything we can to deliver the same experience across all platforms.
Should we decide to do some big expansions or something, we'll expect gamers to pay for it. But again, it's all value for money. I think $15-$20 for new gameplay is a pretty honest and fair deal. But additional weapons and fixes, those of course come as part of the package."
Iwinski also revealed that the Redkit mod tools (the current tool that can be used to mod The Witcher 2) will support The Witcher 3 as well.
"We'll be supporting The Witcher 3 for years after it comes out. We're also building the Redkit, and we'll talk about modding Witcher 3 when the time comes. It's all about a long-term relationship with our gamers. It even works from a business perspective. Abandoning our baby that we've worked on for several years would be crazy. The fact that we have a second game in development just gives us a better way to reallocate resources – QA and whatnot. It's just a better way to manage the process internally. It's better for the people and the team."
The Witcher 3: Wild Hunt will be released sometime in 2014 for the PC and next-gen consoles.