I have read this whole thread with great interest. I am a brainwallet user. In a thread from over a year ago, I learned a lot about the difference between obfuscation and sufficient entropy. Have a look...
https://bitcointalk.org/index.php?topic=350789.0In the end, I decided to stay away from obfuscation. I now use a truly random, very high entropy passphrase. I couple that with a second random and high entropy BIP38 passphrase. My coin are extremely safe.
I read some of the comments. I never understood why people claim that obfuscation cannot add entroppy to the entire system. For example, if there are only 2 methods of obfuscation known to man then using one of them to further obscure your passphrase would add 1 additional bit of entropy.
I agree that obfuscation adds some entropy. However, the mistake people make is in looking at the final resultant passphrase and think it has way more entropy than it really does. The other mistake is in assuming that someone else won't think of your obfuscation.