The most glaring error with "brain wallet" is the many various ways we have of spelling virtually identical words, capitalizing or not, hyphenating, punctuating...

This makes it possible to "remember" a brain wallet and still not be able to type it in and get it right. What is "remembered" is fundamentally imprecise.

Hence I think a predefined word list is a Very Good Idea with anything that would have the beginnings of BrainWalleticity.

Next I'm going to say the last word needs to be a checksum.

Keeping on going, looking like I'm reinventing Bitcoin Improvement Protocols, doesn't it?