Multisig addresses are fully visible in blocks, just like regular addresses.
I was talking about using the bitcoind client. Are you suggesting that bitcoin users should manually parse the blockchain to determine if their funds arrived?
Multisig addresses are not useful as-is. External tools of some sort are required.
The reference implementation could be improved to be sure, but it will never be able to be the whole infrastructure for multisig.
As jgarzik notes, there are tools available already that are suitable for infrequent multisig usage.