And sure, the character of Dr Strange in the beginning of his first movie is not a hero either...that's the point. He has to go on the journey, learning to deal with his arrogance and focus on the greater good. Even into MoM, we see various Stranges that have gone too far, and become villains in their own right. What helps keep our Dr Strange on the heroic path is that he opens up to Christine and America, relies on them for help, and sees how his obsession could lead to the dark side if he keeps pursuing it, so he doesn't push too far.
But at the end of the day, Dr Strange risks himself to save the world...its a heroic act. Now is that character flaw still there....absolutely. Could it lead to a fall in the future....absolutely. Just as Wanda's power and grief have always been ways she could fall. The difference is....Wanda did fall, Strange hasn't.....yet.
That's what makes the hero's path so difficult, its not a one and done. These heroes have to STAY heroic, that's the real challenge in the narrative.