Yeah, I wouldn't do this on non denim - the extra seam would look weird. Not to mention it wouldn't give you much of an advantage. It's the weathered, top stitched hems in denim that are the key to keeping it looking authentic. In most other pants the hem isn't as noticeable, and you can just cut off the excess and do a new hem, either top stitched or blind stitched.
Btw, if you're going to hem denim, make sure you have a denim needle with a bigger eye, preferably a new one so it's nice and sharp. Cheaper lightweight machines often have a hard time going through thick layers of something like denim and having a new, appropriate needle can help a lot.
