Really simple WA that just displays your current GCD (white) and cast time (yellow) as circles around your mouse cursor. The cast circle flashes red if your cast fails for some reason (somewhat inconsistent).
Designed to help me keep track of these things while I heal without having to look away from my raid frames.
Soothing Mist is blacklisted from the cast time circle, leave a comment if you find more spells that should be blacklisted.
UPDATES
7/24 - Increased frame strata since it was displaying underneath grid2 sometimes. Additionally, the cast circle now flashes red if a spell fails to cast--this is somewhat inconsistent, but seems to work most of the time.