The biggest problem of bitcoin right now is trust. Actually the lack of it... Lack of trust in the bitcoin system itself, the software and the companies around bitcoin.
The thing is that only time can fix this particular problem...
I would agree regarding the trust as the currency. BTC has to become a currency, not a speculative asset for gambling. This means price stability/growth stability. Then the problem of a lack of adoption will be resolved. Yes, trust is the most important issue.
That's what I've felt for a while is Bitcoin's biggest challenge. It needs to get over the image of an investment and move on to being a unit of trade.
A unit of trade can still be viewed as an investment. Look at gold, it is the oldest unit of trade that exists today, but many people also treat gold as an investment.
But gold is worth something due to its properties, especialy in technical sence, unlike bitcoin, that has no other purpuse other than for trading/speculating.
If i was to invest large amounts of capital into something like that, i would like some guarantee that:
-it cant be stolen from me without option to file a claim (dispute)
-it wont be banned from existence
-cant be copyed by anyone, ever again.
And due to bitcoin nature as open source software, and ireversibility of payments, it simply makes me reconsider my investment.
I do have some portion invested in bitcoin, just in case something insane happens, but i realise how that is high risk investment, and so should others before they invest.