Shooting stickbows won't mess up your shooting skill with a compound, but it could very well mess up your compound shooting. A lot of guys I know won't have anything to do with compounds since learning to shoot a stickbow.
I shot both for about 20 years. Compounds for competition and longbows/recurves for hunting and fun. When my stickbow shooting went sour, I would get out the compound and work on form for a week or so. Then, when I went back to my stickbow, I would shoot great.
Neither a longbow or a recurve is 'better.' Nowadays, with the reflex/deflex longbow design, a longbow will shoot just as fast as practically any recurve. Some feel a recurve is easier to learn to shoot than a longbow because of the similarity of it's grip to that of a compound. Also, a recurve is more centershot and is a lot more tolerant of arrow spine than most longbows. But, a longbow is more tolerant of the occasional sloppy release than a recurve. Pretty much balances out.
About the sights, there is nothing wrong with using sights on a recurve. I've done it many times. Sights on a longbow is like putting hubcaps on a tractor. They just don't go together. Also, shooting sights on a stickbow will disqualify you from shooting in the traditional classes at 3D, and most all-trad shoots won't allow sighted bows. Don't know if that means beans to you, but you do need to be aware of it.
You might want to head off down the forums and holler at the traditional guys. They're full of information you'll need. Well, they're full of something anyway.<img src=icon_smile_big.gif border=0 align=middle>