I just spent the evening trying to maximize my DPS as well. I have mixed classes though (Fire Mage 20/51/0, Boomkin 55/0/16, Elemental Shammy 57/14/0, SPriest 14/0/57)

I split up my DPS rotation into 2 macros. One to start with DoTs etc (using castsequence).. and my spam macro (using castrandom)

I tried comparing this to just a basic spell spam (e.g., just lightning bolt, fireball or wrath) and I got pretty mixed results. I couldn't reach a conclusion as to what was better.

I did some trials against the highest dummy in Org for 30seconds each. I am guessing that the longer the fight the higher DPS the more "complex macros" will have,given the random nature (i.e., can't take full advantage of the special procs like Hotstreak etc.. that probably make the big difference).

Going to have to spend more time on this unfortunately.

I might try multiple /castsequences with commas within the macro instead of /castrandom (this removes the effect of cast "lag" I believe and provides a sequence) to see if that helps.

Feel free to offer your DPS sequences =)