What's Next? An ability priority Addon with fully customizable logic.
What's Next? is a new addon that suggests the next ideal ability to cast given the player's state and the battlefield conditions.
The logic used to suggest abilities is fully customizable using any of a large (and growing) number of conditional statements from the number of known enemy units to if the player's target is casting.
For more information the addon can be found on curse at: http://www.curse.com/addons/wow/whatsnext
What's Next? is still in early beta and has default logic for only:
Death KnightsBlood
DruidsGuardian
PaladinsProtection
WarriorsArms
Fury
Protection
but logic can be built for any spec/class entirely in game.
Feedback is always appreciated, especially on what additional conditional statements people would like implemented.