I would argue the opposite. Baggy outerwear hides all of the small leg/body movements that can make a trick look bad, and thats because of the sheer mass and surface area of the clothing. tight pants show the real deal, whereas you could do a very sketchy trick and it would still appear legit because you are masquerading behind heaps of fabric.
I wear slim fitting pants occasionally and I think its harder to make your tricks look good in them...