I would love to see a G36 in game. Of course it should be military grade and hard to find. I would also like to see a decent amount of character customization. I don't think you should have to find clothing but you should create a character at the beginning with a wide choice oh helmets, hats, jackets, boots, gloves, etc.
Not sure about the clothing thing... because its likely people will just pick the outfit that offers the most camouflage to give them an advantage in pvp... Plus with the storage on certain items of clothing, I think finding it is a good thing. Although, saying that, they have said that the monetization will likely be vanity clothing etc... so you could get a character looking exactly like you want them too and have it as the texture "overlay" meaning you still get the benefits of clothes you find... but you see the clothes you bought instead. With Jimmy in the team, the G36 will make it into the game... but maybe not on release.
Yes, the clothing would just confuse a ton of people and mess up the game a LOT. The G36 is a sweet gun. It would be a great 2nd choice to m4s.