...it would have to be better in some way other than just "I started the new chain, so I've got a lot of the easy-to-generate-at-the-beginning-coins."
You say that now, but if bitcoin really takes off I can see lots of get-rich-quick imitators coming on the scene: gitcoin, nitcoin, witcoin, titcoin, shitcoin... Some of them are sure to attract users with promises like "Why use bitcoin, where you can only generate 50 bitcoins every few months? Use shitcoin instead, and you'll get 51 shitcoins every 2 minutes".
Of course the cheap imitators will disappear as quickly as those 1990s "internet currencies" like
flooz and
beenz, but lots of people will get burned along the way.