I think copyright is most valuable as a tool to protect someone's work from plagiarism. Preventing others from copying your work without attribution is a good thing. Using copyright to block the derivative or transformative work others make is counterproductive. I like the phrase "rising tides lifts all boats".
I think rules on fair use should be far more forgiving than they currently are. You should be able to protect complete concepts, like a unique character, setting, or story, but you can't stop others from modifying or being inspired by someone's ideas.
I also think corporations or private entities should never be able to own copyright. Copyright must be owned by a person or a group of people (the makers/authors). Ownership of copyright shouldn't be able to be transferable, but you can give permission to use the copyright like a normal license or contract would. That means copyright ends when the last owner does, and the work enters public domain.
Edit corrected with attribution to without attribution
Ignoring the difference between copyright and patents, this is exactly the kind of motivation I'm looking to prevent! The idea that the only driver of invention and creativity is the profit motive is corporate propaganda. Humans have, from our evolution, always been driven to invent and create to make our lives easier.
Using the example of pharma company, if a hypothetical company with infinite funds and resources for their R&D group wants to develop a new drug that cures cancer, despite having infinite input, they will still never produce anything if they don't have people to do the work of research and development. A media company like Disney, despite their vast wealth, cannot produce movies without writers, animators, voice actors, production crews, etc. This is my reason for people being the only ones able to own a copyright. (Edit to fix a typo)