In World Boss events like Baal/Cerb where we have multiple hero stunners casting in formation its impossible to tell if one or both stunners are hitting for stun effect.
If the first hits you can see the swirly star graphics and that is fine. But if the 2nd also hits you get no indication whatsoever to let you know if the 2nd stunner also hit or not.

It is very useful to know this information (multiple stuns) since we can tell if different rune combinations/configurations are improving our effective stun rates or not.

I'd recommend giving a number "2" between the spinning stars if a 2nd stun takes place in the same round or else changing the color of the spinning stars - or make the NPCs head spin in circles like its possessed.

Also, insofar as combat resolution goes a double-stun should carry over into the next round at least in part - say half of the round remain stunned if not being stunned again. Should be a bonus for double stuns IMHO.