for rogues its really tough to determine if you go mongoose or excecutioner on the main hand. my honest opinion is proccing 120 agi means 120 ap, a ton of crit, and a mild swing speed increase. (can't forget dodge) so, thats why its tough. for aa warrior its no brainer excecutioner on mh, cuz you don't get the ap buff from mongoose.
however lossing the seccond mongoose means you can'd double proc it, as well as you have it up less, and yes theory crafting puts dual mongoose ahead of excecutioner/mongoose for a rogue. but hey, if you got mats try it out, it seems like it would be equally beneficial for mut as well as combat.
There is more to life than pew pew you know, like staying out of the fire so you can live to pew pew another day