Cool spreadsheet, I plan on messing with this a bit when I have some free time to test out different things.
Couple things to note for accuracy:
Your character sheet will incorporate talents such as Vitality correctly. It looks like you are taking the value of STR according to the character sheet, then multiplying by the Vitality bonus a second time. Whatever values are shown on your character sheet for STR/Agil/Stam all ready take talent multipliers into effect.
Improved Mark of the Wild applies to the Druid only - and is independant of the buff itself. Warriors (any non-Druid really) can never have this bonus.
Neither of these will likely make a huge difference, but it's still important for accuracy.
Also, something doesn't "seem" right in some of the damage calcs. According to this, my Shockwaves and Revenges should be hitting for ~16k with everything up on a raid boss (and 30% ICC buff). I'm not sure I've ever seen a 14.5k Shield Slam either. I'll double check my stats and see if I did something wrong on my end.
Failure is not an option. It comes bundled with the software.