There's probably a place for both. A starry-eyed optimist might be a description of the pioneers of the world. Some may die as a result of their enthusiasm and some may succeed and try to pass their findings on to those more sceptical and perhaps more fearful and set in their ways.
Kind of misses the point. Yes, we need people to come up with new ideas and to have a certain amount of optimism about them, but the
only way we get to have confidence in those new ideas is after somebody has done their very best to find fault with them.
You neither make make progress in science nor have reliable technology without large helpings of scepticism.
It's the pioneers who don't try to find fault with their ideas (or, better yet, get somebody else to) before trusting their lives to them who tend to end up dead.