The main weakness of Bitcoin and other cryptocurrencies at the moment is that they are distributed systems depending on centralized ones (I am looking at you, banking account) that will probably try to fight them, sooner or later, in order to keep their power.
The only solution would be something that has come up repeatedly from time to time on this very forum and on many others, a decentralized bitcoin exchange (
if possible integrated into the client, you don't want a website that can go down for that) based on a web of trust (a la
http://bitcoin-otc.com/) and including integrated escrow capabilities.
Such a system would allow people to convert fiat into btc by doing regular transactions between individuals, thus drastically reducing any possibility of regulation, or hack for that matter, that could have a negative impact on the price, less FUD, on the other hand, could probably mean a more stable price over the long run.
ps. I don't see Ripple as being a solution, there is no need to add another crypto to the mix in my viewWhat do you think? Is there anything like that on the roadmap? Is there any credible project out there as far as you know? I can help with the design side if someone want to start it
