I looked at that table, interesting. My concersn would be speed of play, and a few other issues.
Speed of play is the most important to me, but already dealt with by others, so moving on...
Another concern is randomness to damage. The random d6 to determine damage isn't influenced by the skill of the player, the skill of the pilot, or any situational modifier--just pure randonmess, and the player has already went through that factor to get a hit roll. It seems that the easier the to hit roll is (4+ versus 10+), the more likely you should be to score to the upper end of the damage scale. But this is a flat random roll--you are just as likely to score maximum damage with a to hit number of 12+ as you are with a to hit number of 2+.
Then there are some unintended effects of the rule that could impact 'mechs with high defensive movement modifiers, most seriously hurting the fastest and lightest units.
Elements with 4 or more damage, effectively, always do some damage on a roll of 6. For Light mechs that live on speed, and keeping target numbers high, this reduces their survival rate, because your chance to do some damage to such a target is, at worst, 16.66% after missing your to hit roll.
Given a targeted element that has a +4 DMM, medium range, and partial cover, (or long range in the open) thats usually 12+(2.78 %) for a 4 gunner, 11+ (8.34%) for a 3 gunner and a 10+ (16.67%) chance for a 2 gunner.
So, effectively, versus fast moving mechs, that ability grants a 2 point bump in gunnery skill to a regular pilot. The fact you only do 1-3 points of damage isnt that helpful as many of those lightsweights only have a combined armor and structure of 2-3 points.
Another side effect:
For units that get most of the bang for their buck from one large weapon, this random damage distribution seems to take away form their capabilities. Lets say you have a unit only armed with an AC 20. When it hits in battletech 20 damage, no randomness in the damage done, translates to 2 in QS/BF. But in this system, that unit has its damage reduced 50% of the time.
It seems the units that do less damage on average get more dependable damage performance for successful to hit rolls.
Averaging the results (adding up the damage results of all rolls 1-6, then divding by 6), then expressing the average done as a percentage of the maximum damage
Base Damage 1 2 3 4 5 6 7 8 9 10
Average Damage 1 1.5 2 2.5 3.33 4 4.5 5 5.83 6.5
100% 75% 67% 63% 67% 67% 64% 63% 65% 65%
The average damage result Favors the 1 and 2 damage dealing units by far in terms out output. 4, 7, and 8 points of damage come out as the leats performing numbers. after 3, 5 and 6 damage returns the best average results for those dealing significant damage (3+).
I just wanted to point out the mechanic has some effects on aspects of play worth noting.