Or, if you had some sort of techno/steampunk world, the hero could maybe create a device that allows them to feel others pain, which gives them a sexual thrill, just like in the black mirror episode, so they start torturing people. This only really works if you're okay with them becoming a sort...
Maybe a good way to do it could be the villain finds some way to make the main character go crazy or use mind control so they torture the villain, and then the hero is exiled and abandoned, allowing the villain to rise to power. I don't even know if that makes any sense.
I think dragons can still be used in new ways, and even if they can't, I'd still say that they're reliable in stories. They've been used countless times, but you can still try to do new things with them.
I'm not sure. When I was younger it was a good way to make friends, and even when we grew apart I carried on with adding to and building off our previous ideas.
For me personally, its only ever been lack of motivation and the presence of distractions. My best way of getting rid of writers block is just to keep dreaming up ideas, so when the block eventually passes, you have plenty of material to work with. This means that hopefully you won't fall back...
Would you say that culture includes other cultures around the main culture, and if so, what sounds like a more realistic background for this concept, a sort of a "we are all one and we all need to contribute" idea, which would eventually collapse, or "what others around us do affects us"?