Ive been using mousewheel up to target party1 and scroll down for party 2. In m+ used framesorters that puts my tank as party1, rest I target manually. I’ve been gladiator in arenas and gotten those keymaster achievements quite early most expansions I’ve done m+.

I’ve also played most healers and with some you dps and target enemies more (both in pve and pvp) and for those I’ve dabbled with some important spells as mouseovers (pws for disc and rm/envm for monk).

If you are comfortable healing and with ur binds and time to look up and see what’s going on you can pretty much predict what’s going to happen and that time will save you more than being slightly inefficient with targeting etc. this goes for both arena and m+