It's something which seems crucial to me for reaching mass adoption (in addition to scalabilty of course...).
Already on this forum there is a shitload of people losing their Bitcoins by forgetting passphrases, the private keys, the dat file etc...
Even if you forget your passphrase and loose your dat file if you are capable of saving your private keys then it is more than enough to use your coins and if you are not capable of doing that then you are not good enough to use any service .It is quite difficult to memorize the passphrases and the only solution is the save everything in a safe place.