I would think that the Pilot Die is far more swingy than MAR is. If you're Pilot Die is a 1, then the max you're going to reach is a 7. If you're looking at 8's to Hit, everything fails. However, without the Pilot Die, one is more likely to get a pair of dice to hit.
Correct. It's more swingy than MAR. It's less swingy than the default all-or-nothing approach to combat in AS. That's exactly why I like it. Some swinginess for drama purposes, but less than all-or-nothing to make it feel a little less like the dice gods have total control over your destiny.
EDIT to add some math:
Take a simplified example where you are rolling for two points of damage and need a 7 to hit. With the default all-or-nothing attack rolls, your chance of hitting (and doing both points of damage) is 21/36 (58.3%). Your chance of whiffing entirely is 15/36 (41.67%). There is, obviously, a 0% chance of hitting with only one point of damage.
With multiple attack rolls, the chance of each point hitting is 21/36. This means that you will hit with both points 34% of the time. You will miss with both points 17.4% of the time. And you will hit with only one point of damage 48.6% of the time.
With a pilot die, you would hit with both points of damage 42.1% of the time. You miss with both points 32.4% of the time. And you hit with only one point 25.5% of the time.
The math obviously changes with different to hit numbers, but the point remains the same that the pilot die option is the midpoint of swinginess. E.g., if the to hit number is 5, the chances of both hit/none hit/one hits for all-or-nothing is 83.3%/16.7%/0%. For MAR, it's 69.4%/2.8%/27.8%. For pilot die, it's 73.15%/6.48%/20.37%. In contrast, for a to-hit number of 9, for all-or-nothing it's 27.8%/72.2%/0%; for MAR it's 7.7%/52.2%/40.1%; and for pilot die it's 13.89%/58.33%/27.78%.
The effect is also more pronounced if you're rolling for more points of damage. For example, if you were rolling for 6 points of damage and needed a TN of 7, your chances of whiffing entirely would be 41.67% as normal with the default all-or-nothing approach, but it goes down to only 0.5% with multiple attack rolls. That's a huge swing, particularly in Alpha Strike where each point of damage is significant. Your chances of hitting with all 6 points are 58.3% with all-or-nothing, and only 3.9% with multiple attack rolls -- also a huge swing. With a pilot die, the chance of whiffing entirely is 7.3%, and the chance of hitting with all six is 24%.
As mentioned, this is very much a personal preference thing. But the thing I most often go back to is when a big-damage mech is unloading on a light mech. Say, something that does 5 points of damage against a 3/2 A/S mech. With all-or-nothing, you're either going to kill that mech or it's going to be undamaged. With multiple attack rolls, you're very likely to partially damage the mech, with instant death or a scot-free escape both being quite unlikely. But with the pilot die, all possibilities are on the table, and that makes it exciting to me.