Both 90's KI and MK has limited visual quality no matter if it was CG or Real Actors. Part of a 'HD version' of something is to make things more pleasant visually. If you can assume that a hd version of KI characters would look like GIJoe Toys, I could easily assume that a hd version of MK would look like poor cosplayers. -> it doesn't look like that sprite, right? So it's not only a matter of looking faithful, but well-done. If a pure hd version would look awful it costs nothing to do little adjustments. A simple design can be improved to become more pleasant to our eyes, with a professional look etc without distorting the original, even if the font is something theoretically limited.