Those correct "romsets" are going to be supported in the near future, but not yet, because of the 3-year-rule of emulation. If you have to play these games now, you HAVE to modify the existing emulators to get them working. Once a few years have passed, I'm 100% sure that those "correct" sets + their clones, hacks, and whatnot will be fully supported. To me, there is no such thing as a non-correct romset, unless someone intentionally distributes bad romsets that wouldn't work properly on any emulator (yes, I've seen those as well, but they aren't so common as you make it sound).