I imagine the whole Silk Road situation has had people looking in from the outside being hesitant to use it, along with high profile dodgy stuff like Mt.Gox. Steps need to be taken to allay their fears and more people would jump on board.
On the whole altcoins angle, it was talked about at one point about Litecoin being the silver to Bitcoin and others being the equivalent of copper etc in that high value, low frequency purchases would be limited to Bitcoin, medium-value, medium-frequency purchases to Litecoin, and low-value, high-frequency purchases to something like Dogecoin or other similar low-value high-volume currencies. That would probably require things like fixed exchange rates, though, which could be problematic. Or unless certain cryptocurrencies were intentionally designed to fill specific roles like I described above, by following a standard of designation such as gold-standard, silver-standard and bronze-standard.
For example, a bronze-standard cryptocurrency would have confirmation times between 5-15 seconds, such that everyday use wouldn't take much longer than the equivalent Visa/Mastercard/etc processing times in checkouts. Silver-standard ones would be more like for use with purchasing more expensive products such as TVs, appliances, etc with 15 second to 2 minute confirmation times, and then gold-standard ones would be for large-scale value transfer and bank transaction reconciliation with longer confirmation times.