As far as I can tell from the information I have gathered on the internet, Dual Wielding works as follows:
1) When wielding two weapons, the speed of the weapons is increased by the Dual Flurry perks. This functions on single strikes, the dual strike and the power attacks.
2) The right hand is faster than the left hand.
3) The dual strike is 50% slower than swinging with just one weapon.
4) The speed of the dual strike is equal to the speed of the left handed weapon.
So, if you consider all of these things, it means that the only combo worth using when dual-wielding is a dagger in the left hand + a mace in the right hand for maximum speed and maximum damage output. Using a faster weapon with less damage in the right hand is pointless because all that you will do is lower your damage and your speed will not increase.
If this is truly how dual-wielding functions, then it is a very shallow and poorly designed fighting system. Whoever thought it up did so in a hurry, and had no clue as to what they were doing in favor of balance. As it stands now, this is the only combo worth using with dual wielding.
So much for variation. If anyone else has anymore information on how it works specifically, I would love to know! I mean, this can't REALLY be how it works?