Jump Transiting Skill
This is the skill of effectively jumping through a point. In tactical jumps, ships are more likely to appear far from the jump point on arrival (up to the maximum of the drive), and in any jump, having a high skill for this provides a bonus to recover from jump sickness.
High Performance Piloting Skill
Replace Fighter Operation with High Performance Piloting, representing skill at moving a ship with relatively high accelleration to avoid damage efficiently through a combination of jinking and feinting. Any ship could benefit from this, but the ratio of Acceleration to mass has a multiplicating effect on this.
The effect is that all hits on a vessel could have a 5% chance to "miss" depending on skill.
This makes all fighters somewhat more useful and strongly rewards smaller, faster ships.
Mineral Rolling Reballance:
Currently, a planet with two minerals at 0.6 accessability is much, much better than a planet with one mineral at 0.9 accessability. This is only natural, as the one with two minerals is effectively 50% better in terms of total tonnage of mineral output.
This is why HW-level minerals are so fantastic- they can easily have a total accessability of something like 7 or 8, meaning your mines are eight times as productive as they would be on a different planet with just one mineral at 1 accessability.
The mineral generator should balance the variety of minerals with the prevalence of minerals. Further, there should be extremely high accessability minerals to enable very attractive, small-term motherlodes of single types, such as you might expect to find in asteroids.
A spread of potential, equally-favorable mining claims might look like this:
Planet I:
Red Stuff: 0.1 10,000 Tons
Blue Stuff: 0.2 10,000 Tons
Green Stuff: 0.3 10,000 Tons
Glowing Stuff: 0.2 10,000 Tons
Clear Stuff: 0.3 10,000 Tons
Reddish-Orange Stuff: 0.1 10,000 Tons
Plaid Stuff: 0.2 10,000 Tons
Planet II:
Glowing Stuff: 0.7 10,000 Tons
Plaid Stuff: 0.6 10,000 Tons
Planet III:
Blue Stuff: 0.8 10,000 Tons
Green Stuff: 0.1 10,000 Tons
Clear Stuff: 0.2 10,000 Tons
Reddish-Orange Stuff: 0.1 10,000 Tons
Asteroid 1224:
Red Stuff: 2.6 5,000 Tons
Gas Giant I:
Reddish-Orange Stuff: 0.4 30,000 Tons
How to actually generate this sort of thing, I'm unsure. Potentially, a planet could first figure out the relative density of each mineral, then multiply those values until, adjusting for the total quantity available, the total accessability reaches a randomly-assigned target value. Then adjusting the dice for the total acessability allows you to ensure there each system having somewhere between 0-2 good planets (TA 4+), a few moderate planets, (TA 1ish) a few bad planets (TA <0.5) and however many useless planets.
By picking a good distribution, you can feed NPC empires better, and you can more importantly drive players to get mining colonies out of the solar system, because right now earth usually has a TA of what, 7.4 or more? And, it can make it add really good planets with TAs of more than 8 which can be interesting points for conflict, but distinct enough for them to be a concern (do I go for this system, which has 1.0 accessability for everything on one planet and decades worth of minerals, or do I go for the system with the 10.0 accessability asteroid full of sorium, tritanium and duranium, which will give me 5,000 tons of each in a few months?)