Emulator

As the main maintainer of Dolphin's support for different disc image formats, there are two major reasons why I don't want to implement this:

1. The code needed for converting to and from the NKit format is very complicated. And as far as I can tell, there is almost nothing to be gained (very little code that can be shared) by implementing it in Dolphin instead of in a separate program. Not to mention that the documentation on the format is a bit lacking on details, making it even harder to implement.

2. While I don't want to make it easier to convert to the NKit format, for the reasons May mentioned (I've spent hours adding warnings to Dolphin to get people to stop using NKit disc images, plus countless more hours providing support to people whose games don't work properly because they're using NKit disc images!), there could be a point in making it easier to convert from the NKit format. Except... anyone who has an NKit disc image either already has a program that can convert to and from the NKit format, or they pirated the NKit disc image. And I am not going to spend tons of effort implementing something that only is useful to pirates.

If you want an efficient format for use with GC/Wii disc images in Dolphin, please use RVZ instead! It compresses even better than the NKit format in most cases (unless you remove the update partition from the NKit disc image only, which is kind of an unfair comparison), it doesn't cause any of the problems that the NKit format causes (other than the problem of not being compatible with old Dolphin versions), Dolphin has built-in support for converting to and from it, and an upcoming update of the NKit app will even deprecate the NKit format in favor of RVZ.