It does too support subtitles, I thought? All you have to do is: when you are in the display mode playing a DVD, just use the keyboard arrows up and down to cycle through a list of configuration options (Volume, Brightness, Saturation, Subtitles) and then use the arrow right or left when on subtitles.
I find that they usually work. Sometimes, unfortunately, it doesn't cycle through as it should so perhaps MC doesn't support all subtitles.