It would seem to me that the aural tests are there as a message to teachers as much as anything else - to make sure they incorporate the purely aural as well as the technical, interpretive and expressive aspects of music into their teaching. If students are consistently struggling as much as it seems with the aural tests, then some teachers haven't got the message and are seeing 'aural' as a last minute add-on just before the exam.
If you incorporate aural training into lessons, as you should, then the tests pose no problem at all, so why don't we just do this instead of griping about the aural tests? I find the kids enjoy it if you treat it as a game: 'lets play some aural games now' and make up your own versions of the four tests, plus others of your own. Recently with a seven-year-old I've been doing 'call and response' with her on our violins as well as with singing (so she has that option in the exam as well as singing back the phrase) and she's becoming remarkably good at it to the extent that she's now learning to play quite complex tunes by ear, having built them up phrase by phrase. I'm intending to extend this to all students so that 'aural training' becomes an integral part of all my lessons. Yes it takes up a bit of time that could be well used improving technique etc etc but I see aural traning as incredibly important otherwise we're in danger of creating technicians not musicians.
If you incorporate it into lessons the aural tests can end up being the easiest part of the exam, not some weird add-on. I always loved the aural tests as a child because I knew I could do them (sorry) - this was because my mum had received a fantastic aural training as a matter of course at school in Vienna, which she then duly passed on to me as a matter of course. Children are such cyphers and all the kids I've done these aural games with seem to love them, especially when you put the boot on the other foot and get them to test you. Pretend to get the answer wrong and then get them to explain your mistake - watch them gloat and explain it in impeccable detail ('you played two notes there when there should have been one! You went up at the end instead of down!') Not too often though!
They really enjoy it because neural pathways open up and it awakens their curiosity and makes them feel intensely alive - you can see it happeneing; you really enjoy it because you can see the learning process at work, which is always wonderful - everybody gains so why don't we just do it and equip our students with good aural skills as well as technical/interpretive/expressive skills, and apart from anything else (like the lifelong benefits) an extra 18 marks can be accrued in an exam without all that last minute panic.