I think they want you to get a feel for Medium, so that when you turn light, you could be like, "Wow, these Lights are really, really weak, lol!"
Thats what I'm going with. It sounds like SDs general message for this game is, even if your a noob, you're welcome here. So, theyll start everyone out with a well rounded body type, gun and skill base. From there, each person will have to grow into their playing style. Its not a bad formula when you get down to it. I'm still alittle uspet with a few aspects of the game but this "tree" type formula I'm all for.
Everyone starts out with a basic grunt and from there you branch out into your style. Hopefully (if its included) if you're not able to eventually unlock EVERYTHING for a single character..you should see a huge diversity in enemy combtants and styles.