The look changes nothing. There are also no better swords or anything like that. It's just what people like more. Some people can spar better while been "naked" other while being pimped by big helmets and so on. With the sword it's similar. Some people can spar better with a big sword because than they know where the attacking range is, other people can spar better with a smal thin sword, so they actually know where they are hitting but the other player isn't under your swords image. It's just up to you and what you see/like more.