Alright, after reading through this long-ass rant, here is my opinion:
Just make the auto-sprint break when you collide with a block, just like normal sprint. Personally I believe auto-sprint just fixes those bugs that normal sprint had, the random breaking wasn't meant to be, it was because of your keyboard randomly stopping and starting that letter again, I've read through the minecraft code, it wasn't meant to do those random breaks, just to stop when colliding with another block (unless I missed something which is doubtful).
Basically you're yelling at a bugfix that makes sprinting easier, yes I suppose it used to let you sprint in other directions. I agree that was OP, but now there is no reason for this.