i wouldn't be climbing on rainier if i thought that the cooper spur was too much - sure it's got a lot of exposure, but it's easy ground - slow n' steady n' w/ a 2nd tool and you're a god - once you get off the bad fall line down the n face you can bomb down it like a crazy man too!
there really is no beating the crowds on the s side - if the weather's halfway decent you'll have plenty of friends
if you havne't climbed hood b4, the s side's cool - but if you want to spend a night or 2 out and really see the mtn from its best side, the n or w sides are where its at