I wondered that since each currencies address is distinct, there might be an opportunity to make life simple for merchants and have one address that can accept all coins.
?..
It would make life even more complicated. Every customer in BTC already gets its own adress so it's easier to track transactions. There'd be no real advantage between generating one or 5 adresses since you'd have to give 5 different prices and check 5 adresses.
That might work for donations,but you would have to inform people that you accept donations in altcoin and there would be lot's of idiots who donate the wrong altcoin to a charity that doesn't accept that one but has a adress that does. Or to the wrong adress like spikey ...