Dice effects "problem(s)"

This is a fine example of a distribution problem combined with what players actually want.
So I have these set of rules. But the players that where willing to test my game had several questions about the dice effects for me:
- Can the upgrading be simpler? Meaning a simpler sequence to follow.
- The Dice effects distribution has a certain hit once an unit has reached level 3 (starts with 0). Can this be removed? So no matter how strong an unit becomes. There is always a chance of missing the target.

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The mechanic as it is in the game:
Level 0 is the default level for any projectile. With a dice you can throw 123456. But the effect would be 001122. (The sum is 6, out of 6 is an average of 1)
A result of 0 means no hit.
A result of 1 means the projectile hits the enemy.
A result of 2 means the projectile hits the enemy twice!
One battle has about 20 projectiles flying on average, so 20 dice will be rolled for this.

Once an unit has enough XP, it can spend this XP on the upgrades.
One of those upgrades is the Dice effects.
In an old version, each upgrade would add a 1 to one of the results. And 6 levels would mean that the unit doubled in damage. The average health was 6, thus 6 rounds on average where needed to kill an unit.
The levels where:
0=001122
1=001123 (+000001)
2=001223 (+000100)
3=011223 (+010000)
4=011233 (+000010)
5=012233 (+001000)
6=112233 (+100000) (The sum is 12, out of 6 is an average of 2, no more miss!)
The + addition repeats after level 6. Apparently rather confusing. Right?

In a newer version, I had to reduce the health of 6 down to 3. This due to balancing.
However, I reduced the levels as well by scrapping half. Simply because I wanted the Dice effects to be equal to the Armor effects. The list was reduced to:
0 was 0=001122
1 was 2=001223 (+000101)
2 was 4=011233 (+010010)
3 was 6=112233 (+101000) (The sum is 12, out of 6 is an average of 2, no more miss!)
Ok, agreed, the distribution of upgrades is now really confusing at first glance. Although, I did say in the manual, 101 on the right, 01 and 10 on the edges and then 101 on the left. Which is less confusing then the previous version. I am prepared to go back to 6 levels, and simply making the XP costs 50%.

The reason that I had chosen for this is that the dice effects are kinda like a linear line slowly climbing, but staying linear.

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The players asked 2 questions, but those 2 are a combined problem for me. If I make it so that throwing 1 with a dice means a miss! after any upgrade. Then I also need to change the upgrading along with whatever default I choose.

I have already set up some self applying rules about throwing dices to make it as simple as possible and :
- The results are always ascending from 0 to higher.
- The default has as highest result the maximum of 3, I simply don't want it higher since health is 3 on average.
- The default has to have at least one 1 as a result. Since this is the basic amount of damage.
- There has to be at least one result of 0=miss! at all times.
- The sum in the default is of course 6. So an average of 1 is met.

This gives 4 choices for the default:
000123
001113
001122 *
011112
I don't know what players prefer, but I had chosen the * since it has equal distribution and does not allow instant kills. Anyhow, each of these 4 are good to go.

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Following up on these rules, I have now 2 choices:
- If I choose 6 levels, then each upgrade will add 1. There are 5 choices in this. And thus rather easy.
- If I choose 3 levels, then each upgrade will add 2. There are 5 choices with +2 and 10 choices with +1. More options for me, makes it harder for me.

But not all the upgrades will have the desired effects regarding the first set of rules.

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So plenty of choice in the upgrading. But what is the end result -sort of- going to be? And this is where I could wish the most for advice from you guys.

What would players like to see (what should be my goal)?
- Different amount of levels between Damage and Armor? Making things easier for me, and probably for them too? So back up to 6 levels for a double damage effect.
- A linear progress for the Damage? Meaning that after a X number of levels. The results follow a neat line from 0 to the highest number? Example results: 0-2-4-6-8-10.
- A lesser linear progress for the Damage? Meaning that most parts follow a linear progress, but the end part increases more? Example results: 0-2-4-6-8-20. That 20 can be lower or higher, of course.
- Some sort of exponential progress for the Damage? No linear progress. Example results: 0-1-3-6-10-15
- Or simply leave it like how it is?