This is a beautiful quilt, and although I understand how frustrating it must have been for you, I think it was well worth the effort you put into it.
I know what you mean about "off grain" - I'm working on a panel at the moment (also birds, but printed on circles so each one looks like a dinner plate) and I nearly gave up!! In the end, I did what I could with cutting, then framed each one to try and centralise the individual panels. Only the encouragement of friends kept me going!!
Don't wait 5 years for your next one, you do too good a job to wait that long. Make another, but this time keep it for something to do in between other quilts. That way you won't have to tackle the difficulties all at once - it will be something you can pick up and put down when the aggravation gets too much!