Back to the original post and question...
Along with QHs and Paints, the Appaloosa was promoted as a viable, versatile stock horse, used in many of the same disciplines as the other popular stock horse breeds. In the early days of the ApHC, there were many foundation stallions who lacked up close QH ancestors:
In striving toward breed improvement, and to work toward a breed standard that would hold up to the other stock horse breeds, some of the earlier foundation Appaloosa stallions achieved much success, even though they had no QH parents. If you didn't know who these stallions were, many would claim they had QH up close:
And, still breeding toward a breed standard and ideal, responsible breeders turned toward good QHs and TBs to get the quality conformation, substance, eye appeal, and superior performance ability, all while retaining pattern:
It's not difficult to see the breed improvement taking place throughout the history of the Appaloosa horse and ApHC. The latter horses were obviously an improvement over the first ones pictured, in terms of overall conformation, balance, substance, performance ability, and eye appeal.
As with stock horse breeds today, responsible breeders should breed toward breed integrity without buying into the corruption and extremes that have plagued the specialized horses. These horses were known for their versatility, and the QHs have excelled at that above all other stock horse breeds. Breeding for versatility while utilizing excellent outcross blood has proven to succeed toward maintaining the integrity of the breed.