Prince of Spires
Istar
In those situations, the magic serves a different purpose in the story though. In Soft Magic systems, the magic isn't there to provide solutions, it's there to provide worldbuilding, tone, and wonder. It's Sanderson's First law:I do agree with Queshire: magic that can't be explained or improved at all is not that interesting or effective as a dramatic device, IMHO.
An author's ability to solve conflict with magic in a statisfying way is DIRECTLY PROPORTIONAL to how well the reader understands said magic.
If you want to solve the climax of your book with magic, then you need to make sure the reader understands said magic. However, if that's not the goal, then the reader can just know it's there.
Also, a reader doesn't need to know all parts, just some is fine.
Look at Star Wars Episode 4, A New Hope. Luke Skywalker blows up the deathstar using the force. As viewer, we no almost zero about the force. The only thing we know is that it's some ancient force which can guide your movements, but that you need to accept it and believe in it. That's all we need to know and it creates an amazing climax when he decides to accept and use this mysterious force. Personal opinion, there's nothing dumb there.
Gandalf is the same somewhat. He's basically an angel doing divine stuff. We don't know the extent of his power or knowledge. However, we don't need to. Why? Because Gandalf doesn't solve anything important with magic. Maybe his fight with the balrog. But most of the big moments in the books, Gandalf either doesn't use magic, or he's vey much absent. He's there to provide a sense of wonder, talk people into getting off their ass and doing things, and as a mentor to make the hobbits feel small, not to do magic. We don't know, we can't know, and that's fine because we don't need to.
That is very different from a story like Mistborn. If that didn't have a hard magic system, where the reader knows exactly what is and isn't possible, then the book simply wouldn't work.