I hope those more expert in brandables than me will respond. Here are my thoughts...
It is a bit longer than optimum, but within range of length used in brandables.
While sometimes a close spelling is used as brandable, for me this is not that great - but I may well be wrong. I think it is because it has 2 differences from the main spelling and that aunt is the ending of the word that make me feel negative.
I do like that it is a play on a positive word (brilliant).
I do like that brilliant could apply to lighting, consultants, education, games/books, and many other areas.
If I was in charge of a brandable marketplace I would probably not accept it, but I might well be wrong. Have you tried submitting it?