I've recently returned to land of Warmachine, and apparently that's where my dice karma moved to long before me. My sample size is incredibly small, but in my pair of MK2 games I've played so far: my dice have been rolling...average. At one point I even rolled three sixes on three dice! Warmachine's system has the benefit of being Gaussian. For those non-math nerds who don't want to read the wiki article, this means that the random values in a set cluster around a single result. For 2d6 that value is 7. As you move away from 7 the likelihood of rolling a given number decreases.
In 40k your rolls can be all over the place because each roll is its own distinct event with its own probabilities. With war machine you have at least two dice affecting a single event, so the random nature of one die is tempered by the random nature of the other. In 40K if you roll for two events and roll a 6 and a 1, you've had a good time, and a bad time. In Warmachine if you roll for two events, one being a 6, 1 and the other being a 6, 1, you've had two average times.
Warmachine also has a way built into the game to adjust probabilities. You can make sure important shots are more likely to hit; something that is not generally possible in 40K. When I'm playing Warmachine I'm less likely to throw a temper tantrum over dice. Of course there is plenty of other BS things to get pissed about during a Warmachine game :) (note: some of those may or may not have been nerfed in MK2)
One thing I don't like about Warmachine's implementation of 2d6 is that the stats don't quite map to the probability curve of 2d6. In Warmachine you compare an attack stat to a defense stat and the difference is the target to-hit roll. Say you have an attack stat of 6 versus two separate defense values of 13 and 17. You need an average roll of 7 to hit the first one, and a very unlikely 11 to hit the second. In this case a 30% increase in defensive stat can result in a 50% decrease in the probability of hitting. This kind of math must make balancing Warmachine a real chore.
I tried to overcome this problem in my own game. Though I'm not sure if it is the best solution.
I guess the point I'm trying to make is that I like games where the random chance is a bit less random. I like 40K for a lot of reasons, but the single d6 mechanic is not one of them. Unfortunately, I can't think of any other option for providing random results in the quantity needed for the average game of 40K