I haven't played in a few years, but I prefer to play mechanically intensive classes usually. What would be ideal?
Often the most mechanically intense are shoved into a macro because they're almost impossible to track single handedly. For example druid for cleric just wouldn't be played without a macro unless you learn a ridiculous amount of 'situational algorithms' so that's at about 80-90% potential (still strong though).
I know defiler is tricky to play because the cds are hard to track, and therefore an addon is essential. No 1 button macro available for them due to the lack of cds with dots.
I really only have experience with Cleric but there are obviously similar souls within other classes.