In a group of mobs, I have no idea who is casting what right now without the ability to see casts.

Already planned. Leaving open for tracking.

Edit: there is a small chance this will get in for pre patch but do not plan on it. It will be in place before the expansion launches.

Initial Support added in a50c8e2 and Released in 4.6.3

Cast related items still to be added:

• Castbar Text (will need to auto increase castbar size if on, default will be off)
• Cast Interruptible indicator

Castbar Text added in 2d1f88a