Sounds like a good idea to pursue.
The "cleaner teeth" you mention might be more a function of the bones in a raw diet. I am uncertain if pre-made raw food includes bone in the form which would aid in pearly whites. I'm mostly certain that the pre-made raw foods include bone but maybe in a ground up fashion to satisfy the bone requirements for a dog eating "raw".
Seems like you are headed in a direction to see if a raw diet will benefit some of your dog's lesser health issues...i.e. scratching..allergies...it's certainly worth a try.
This might lead you to a diet for your dog which consists of "rawer" version than a pre-made raw diet.
It is important to make sure, if you do it on your own, to get the requirements properly fulfilled for your dogs.