I use the high brace frequently... and there are multiple situations where it is the stroke of choice.
A proper high brace has the elbow down at belly button level and close to your body, and your shoudler is all the way down. Wrists are at shoulder level with the power face of the blade down.
A high brace executed from an aggressive forward leaning position can be used to ride diaganol waves and to keep from flipping in turbulent drops.
The wrong way to do a high brace is to let your elbows come up and away from your body, let your shoulder rise up, and let your hands come up at near head level.
Its easy to tell beginners never to do a high brace, but for more advanced boaters, the key is knowing when and how to do a high brace.
Bummer about your shoulder injury.