Well, without the cutscenes, the Injustice 2 story might last you approximately 12 hours, give or take. This assumes you're playing at a decent pace and not getting stuck on difficult sections for too long.
I think Uncharted Story is good. The way it unfolds keeps you hooked, and the settings and action scenes are well-done. But, of course, it's subjective - different people have different standards for what makes a story good.
Sure, the Destiny 2 beta allowed for skipping cutscenes in the story. It's a common feature in many games these days to give players more control over their experience. If you're not into the story part and just want to get to the gameplay, it's there for you to use.
The cutscenes are very important. They help to tell the story. Without them, we would not understand the context of the medical cases or the relationships between the characters as well.
First, think about their backstory. For example, if they're an adventurer, what led them to this life? Maybe they grew up in a family of treasure hunters. Second, give them unique skills or flaws. A skill could be expert marksmanship, and a flaw could be a fear of heights. This makes them more human. Finally, tie them into the existing Uncharted world. Maybe they have a past with one of the existing characters.
Perhaps an OC is a young archaeology student who idolizes Nathan Drake. They manage to get involved in one of his expeditions through sheer determination. Along the way, they learn from Drake and also teach him new things about modern archaeological research methods. It could be a story of growth and adventure for both characters.