opinions on dps split?

[alsims2007]

There is no real difference if both focus 1 down vs split . But splitting while doing Aoe and multi dotting is better than both. What really should happen in combat with 2 enemies is the dps should dot both and spread to maximize the dot ticks. Let's say it's like you examples and 2 enemies will die in 30 seconds (preferably longer cause I wouldn't use tod in a 30 encounter) , as a monk, I'll demolish one, touch of death the other, then switch back to the other for the other single target skills and demo the other before once again returning to the first mob. The switching gives the dots time to fully (or close to it) tick which on monk is the difference between using a 180 potency skill and a 350 potency skill.
Sometimes killing 1 thing faster is slower overall if you can't let the stronger dots tick for a certain length

[spelley]

As others have stated, the benefits of focus firing usually revolve around lowering incoming tank damage, as well as reducing the number of AOEs and such that can result in party damage/mistakes.