I have to agree that some parts of BA's assessment process, especially the micropat tests for direct entry pilots seem a bit strange. However I have been through the system twice now, one many years ago for the Cadet scheme and one more recently for direct entry.
I think the key is the interview, and with it preparation. If you go into it without any thought (as I did first time) you have no chance. They are looking for people who not only want to be pilots, but who only want to work for BA, whether you want to or not, you have to convince them of this. And this takes preparation. To give you some idea, I put in probably 100 hours of work or more for my latest attempt at BA - the result, success.
So if you want it enough, go for it, but don't be half hearted or you may as well not turn up.
Good luck to you all, I hope it is worth the effort.