tumblr. do it.
"or slimmer trousers , this looks like a mess down below :S"
tbh I think that if he just unzips it fully they won't be a problem
the proportions right now go from slim/long to bulky/short, though if he opened the jacket the whole top wouldn't be as slim (like in reality maybe, but not to our eyes) and also, there would be no upside-down triangle enhancing the previously mentioned proportions = really nice fit with better proportions.
but then again, right now I don't have any clothes similar to the-arms, so what do I know