Is there an easy way to compare a staff with a one-handed weapon + off-hand?
Solution 1:
I use Pawn for this.
Pawn gives every equippable item a score based on stat weights for your spec (you can also specify your own weights, determined by tools like SimulationCraft). When you compare two items, it will annotate the score of the better item:
But, by default, it will compare the combination of main hand and off hand to any two-handed weapon, so even if a dagger is worse than the staff, Pawn will mark it as better as long as the off hand item makes up the difference.