I think that brain wallets for Stellar (something like Bitcoin's BIP 39) can actually be useful. The main use case is an offline wallet you want to store in a safe place with a larger amount of cryptocurrency. In Stellar, you are OK with simply storing your account secret key (or keys for multisig) but the thing is you can make a mistake in one or more character when writing it down. [1] With brain wallet it's not an issue because words you write down are selected in a way that eliminates similar words and mistakes. And if you really want to store your wallet in a brain, it's much easier to remember 12 words that 56 characters.
I wrote this doc recently with a similar idea but using emoji ?. https://gist.github.com/bartekn/c877987b722ec792912d720921a7418c Looks like a joke and was meant to be a joke but if you think about it, it can be useful if you put emojis in a 16x16 grid with each emoji in a standardized position. It should be easy to remember, I need to try to implement this finally.
You should definitely post a link to your app here.
[1] Obviously for larger amounts you should try to send small amount first and see if you can withdraw it using the process you will be using in a future.