Agreed. We urgently need a user-friendly import/export function in the client!
I'm sure it's coming. I've learned a lot compiling Bitcoin myself, though. Bitcoin is still very young, and still needs a lot of work to be completely usable by the masses.
This is the most secure "wallet" there could possibly be. No no copies of wallet.dat, no encryption, no USB stick/paper/printing which can be lost, no malware which secretly steals my coins, no storage or bank vault, no life CD, no nothing! Just a simple passphrase I can remember. Since nothing is stored or written down anywhere this wallet concept is basically impossible to compromise.
The only flaw is that I might forget my passphrase, but I can still write hints/clues which can make my help remember while still being 100% secure. We need this.
I'm pretty sure that it'd be much more secure to have a completely random number for your private key (as Bitcoin does by default), encrypt that number with your passphase (such as say encrypting your wallet.dat with TrueCrypt as some people do now anyway), and store that on "the cloud" somewhere if you're worried about losing it. With the amount of hashing/computing power already in the hands of bitcoin enthusiasts, trying to hash all dictionary words and passphrases up to a few words and seeing if they're the private key to money in the chain is going to be a lot easier than needing to find wallets and brute force each one separately. My sense of scale may be deceiving me, but that's my intuition at least.