Guess a lot of us use shamans with a pally, so lets take those as example.

Shammys have flame shock on a 6sec cd, they have chain lightning on a 6sec cd

Whenever I solo play (and since i havent multiboxed 5 in a loonnngg time) I use cast sequence macro's for my pally, why? because I like to play this way. But perhaps somebody else can have some advantages from it. I use 2 macro's on it (see it in action: http://www.youtube.com/watch?v=SPJP-LE2dIE)

Macro1 - 6s cds
Code:
#showtooltip 
/console Sound_EnableSFX 0
/castsequence Shield of Righteousness, Hammer of the Righteous
/console Sound_EnableSFX 1
/run UIErrorsFrame:Clear()
Macro2-9s cd's
Code:
#showtooltip 
/console Sound_EnableSFX 0
/castsequence judgement of wisdom, consecration
/console Sound_EnableSFX 1
/run UIErrorsFrame:Clear()
What I do is, use my holy shield, walk in, press macro 1, then macro 2, press 1, 2, etc. Due to the cast sequence you get the next spell every time, so the right spell would be available for usage. You can keep up a reasonable 969696 for your pally.

What if you just made the same kinds of macro's for your shammies?
Macro1 - 6s cds
Code:
#showtooltip 
/console Sound_EnableSFX 0
/castsequence Flame Shock, Chain lightning
/console Sound_EnableSFX 1
/run UIErrorsFrame:Clear()
Macro2
Code:
#showtooltip 
 /console Sound_EnableSFX 0
/use 13
/use 14
 /castsequence [insert shammy normal dps string]
 /console Sound_EnableSFX 1
 /run UIErrorsFrame:Clear()
Makes you a little bit more versatile and able to have some situational choises while playing instead of whiping + redoing buttons.