Fundamentally this is a great soup!
My carcass was from a 14lb Turkey. Most of the major parts were eaten, but there was still a considerable amount of meat on the bone.
Per other comments,
added two capfuls of Apple Cider Vinegar during the boiling phase
50% Chicken stock to water
Primary ingredients:
Double carrots
Double celery
Double barley
Add 4-8 cloves of garlic
Skipped tomatoes (might reconsider)
Seasoning:
Double Worcestersshire
Double to triple salt and pepper (to taste)
Double parsley
Double Basil
Double to triple paprika
Double to triple poultry seasoning.
Double thyme
Add red pepper
Add a couple good squirts of Sriracha sauce
And I found myself adding a fair amount more water, to handle the additional barley and also to make the soup a bit thinner. Particularly as the water evaporates over the course of the day.
I can attest that these modifications result in a properly hearty soup!
Oh, I also learned how to properly dice an onion today:
https://www.youtube.com/watch?v=TwGBt3V0yvc