If someone were to say, have impervious scales and tougher organs (but still squishy, like maybe a bit tougher than human organs), would internal bleeding still be a major issue? They get into plenty on fights where they're knocked around by large fists, solid objects, and swords.
Absolutely. Internal bleeding has many causes, beyond fighting. It's more likely to happen in the abdominal area, the bleeding closer to the liver and spleen. It also can happen in the head.
Tougher organs would likely be better off than human organs. They wouldn't jostle around as easily, at least in the abdomen. The head would still be as vulnerable.