Before Bitcoins usage is expanded multifold from current figures, two key issues need to be looked at (and i know they are under future consideration)
1. Transaction confirmations need to be done faster than the current 10 min's in the blockchain
2. The blockchain needs to be optimised somehow to reduce it's size; a possibility of having 2 "linked" blockchains , let's imagine them as mini-bc and big-bc, where the mini-bc will have a subset of info in the current main bc.
Neither of those are required. The first is already solved by many of us, using green addresses and assuming very tiny amounts of risk. You do not need to wait for a confirmation to give your customer his hamburger - as soon as the transaction is seen, it's extremely unlikely that you'll get ripped off for $6.50. Much more likely that you'll die in a car accident driving home from work.
The second is probably a good evolution, but is not required. Not everyone needs to have the full blockchain to use the Bitcoin network. Many solutions to this already exist (ie - every ewallet, and thin clients).
What DOES need to occur before any "nation" would ever consider adopting something as experimental as Bitcoin is for the exchange rate to calm down considerably. The Bitcoin network has proven beautiful and resilient, but the market price will be chaotic for a long time while humanity tries to price this crazy thing. Until the price is very stable, it doesn't make sense to place what should be conservative money into Bitcoin (I'll also speculate that the price will not be relatively stable until Bitcoin is at least a few hundred dollars, if not a few thousand - the market will be too shallow until then).
Bitcoin does not require, nor does it lend itself well, to state sponsorship. What we need are individuals, wherever they are, to discover how Bitcoin works and realize why they should opt out of fiat incrementally.