Leader Trait RNG is like Tech RNG. If you don't like it, expand the number of options via Leader Trait options. Meritocracy Civic + Aptitude Tradition(which people crap on for good reason) are ways to generate additional Trait options. Rushing Genetic Ascension would do a lot for you as well since Erudite comes with +1 Leader Trait picks(and +1 Research Alternatives). If you go hard into Purity, then you can generate additional starting Traits(which stacks with Aptitude).
With respect to Aptitude, I have three upgrades for it that would instantly catapult it to among the Traditions I would always use. The finisher for Aptitude would increase the Level Cap for Leaders from 10 to 11(or ideally 12). The bonus level cap results in more Veteran Trait picks, additional perks from their respective class(Fire Rate for Fleet Admirals) and coincidentally stronger Councilor perks. Second change would lower XP required by 10-20%, enabling Leaders to level up much faster. Final upgrade is with regard to Negative Traits. Aptitude and Harmony are the only Traditions with Maximum Negative Leader Trait perks but even with that and Erudite(which also yields a -1), you're still subject to getting Negative Traits at random without additional Negative Trait perks via Talented, Elevated Synapses or having two Flexible Traditions from Purity Tree(which grants another -1). To safeguard your Leaders from being ruined by RNG, Aptitude's agenda would yield 5% XP gain(ramp up) and 20% XP at launch while removing all Negative Traits at the cost of 500 XP each. You do those changes and Aptitude would be S-Tier.
