I guess some of the problems will eventually be solved, like usability and security for the average joe, insured exchanges and custodians also already happening.
I can only think of regulation and fraud, that can really stifle bitcoin's adoption.
Yeah, I think usability is not too bad at the moment for average people it is just about them getting their head around how it works. THIngs like the address book to store friends addresses and how easy it is to see how many BTC you have.
I think the big problem is about them learning how bitcoin works and wanting to use it after they hear about it.
You can explain to them how bitcoin works in a simple manner, without those jargon and whatnot. If you want other people to believe in you, you must try not to scare them by mentioning several technical details and jargon that may lead to their confusion. Same with bitcoin. You needn't explain to them the algorithm or the other technicalities that bitcoin has. They only need to understand the basics, like what is bitcoin, what is the block chain ledger, what is an address and how to store their bitcoin safely. In that way they might adopt the currency and help the bitcoin economy. But if you try and explain them with a nerdy approach, you'll probably scare them away,
You use fiat and never asked how it was made, right?