What do you need a SIGHT for? Use the arrow.
If you're going to shoot a bow, SHOOT the bow. Don't rely on cheap mechanical tricks.
when i was a kid, i used to have one of those cheap k-mart special fiberglass bows. i was pretty good with it.
wheni got back into archery a few years ago, i was kinda intrigued by the compound bows. the speed of the arrow, the ability to hold, due to drop off, and the sights.
even with sights, you still need skill. it's definitly harder to shoot a longbow without sights...although i've seen guys that have sights built into the bow itself........
but what it comes down to, is that it's just a different skillset.