Also, there are plans to implement deterministic wallets for the reference client too, as the advantages for backup safety far outweigh the security risks.
This is a very good point. A non trivial number of coins have been collectively lost over the years due to the "gotchas" inherent in a RBOK (random bunch of keys) wallet.
Just some examples:
a) failing to make a backup
b) failing to keep backup current and exhausting the keypool
c) forgetting or losing passphrase and not having a paper backup
d) encrypting a wallet and not making a new backup (encrypting results in keypool being flushed and old backups out of date)