Earth shock rank 1 for spell interrupt, R.I.P.

Enjoy being OOM on fights like VR, Tidewalker, and most of hyjal. You will love Kaz, considering half your mana will be gone just to him.

Downranking you can top off a tank taking light damage in anticipation of a huge hit coming. When that huge hit comes you hit the big version. Your mana efficiency is much better and you will be able to last longer.

All this talk of downranking reminds me of one of the Discord mods I used to use. It would auto-downrank based on how much healing someone required. Also, if you were low on mana, it would auto-downrank to whichever rank you could cast with your available mana.

Also, it could auto-target the lowest-health raid member.

All of this could be done with a single button, so if I was feeling lazy (like during MC runs) I could just hit my autoheal button repeatedly and I'd perform pretty decently. Ah, memories.

Of course, none of that stuff can be done with addons anymore. :)

Was the rest of your group new to Kara? You likely weren't OOM because you didn't need to be endlessly spamming heals, which is what most of raiding is.

I hate to take the bait and call you a noob, but you are new to raiding, so please don't condescend to those of us with more experience: We know better.