when less experienced drivers (of course, not all of them) get short shifters, they tend to shift too fast, letting the clutch out too early, and end up grinding gears more often. that is what causes the added wear from a short shifter. as far as the actual shifter doing it, i can only imagine a really low quality shifter that causes funky shift linkage geometry to mess up a transmission, but usually you would know that right away before u even drive the car...

so all in all, if you drive normal, and not all speed shifter style, you should be fine.