I think your thinking on the farm dog is incorrect.
A failed farm dog is probably anxious, neurotic and unsure hence why a failed farm dog. Farm dogs have to be courageous intelligent and able to work with loads of distractions around them.
I have three collies - the farm dogs are way more chilled than the obedience breed collie.
They have completely taken over my life. I have always had dogs but the moment I got my first collie things changed 
They need mental stimulation so two walks a day is just not enough for a collie.
I changed career because of my dogs as it was easier to fit their needs into my day , my social life is around the collies (loads of agility).
I am happy to make the changes but having a collie will mean you have to put their needs first or you will have a stressed collie and your life will be hard very hard.
A collie that is not stimulated will go self employed and that is very hard to live with.
Collies can be noise sensitive - which can be hard to live with, they can find adjusting to new places hard, can not always like people, need space, can be very herdy (hence the nipping that your dog is doing and that is very hard to train out of them).
Collies are without doubt very intelligent dogs but do you ever wonder why they are not used for assistant dogs 