For me an alt-coin needs to do something that BTC can't , or do something much better than BTC and have a sustainable ecosystem. Frankly I do not see many such coins in the alt-coin universe. Instead what I see is a lot of vapour ware coins based on some "dodgy" white paper, that have no credible technology road map, and no developer network to make that road map happen. Worse many of these coins have huge pre-mines so the only people getting rich are the founders when they exit at the expense of the investors.