Funky sound choices
If you can't get a vocalist to do this, a better sound for the vocal melody line might have been a great improvement. The backup sounds great from what I can hear, but the main line takes away from that and makes it harder to enjoy.
Also, one thing people sometimes forget about the Beatles is that they have some sweet harmonies in the vocals, so that would have been good. If you could tone down the main line some that would be good too- it's a little loud and piercing.
Overall, sounds decent, but not great.