Who said untrusted? The proposal is that you distribute blk0001.dat (and only blk0001.dat) in the bitcoin.org official client downloads. And of course the client will spend some time verifying blk0001.dat upon first use. This is unavoidable, and nobody has proposed changing or eliminating verification.
Just shipping blk0001.dat with official bitcoin would eliminate several headaches that new bitcoin users continue to experience.
My personal suggestion is to have the block data as a separate download, but strongly recommended. If you want to simplify the installation for Windows users and otherwise clueless computer users that can't take a block file of this nature and put it into the correct directory, perhaps setting up a formal installation file to put it where it needs to go would be more "user friendly", but all it really has to contain is just the block data.
The purpose of this is mainly so those who are updating to a new version can do so without having to also keep downloading the same block data, which by definition is going to grow over time.