Guild Wars 2

Separate the minor and major traits in each trait line to a separate line for minor traits and major traits. This way players can choose more health, damage, damage mitigation, critical damage without having to be required to choose only those minor and major traits in those lines. Each minor and major trait would have a separate line of tiers and points to add to those tiers so that traits stay balanced and do not overpower a character.
Another proposition would be to add separate minor and major trait lines in addition to existing one and add new minor and major traits to those and move any existing ones to the new ones if needed.
example:
+points to
power-line—->minor trait—>major trait—>next tier—>power-line—>minor trait—>major trait
+points to
co-power-line1—> minor trait—>next tier—>minor trait…
+points to
co-power-line2—> major trait—>next tier—>major trait…
+points to
precision line—->minor trait—>major trait—>next tier…
+points to
co-precision-line1—> minor trait—>next tier—>minor trait…
+points to
co-precision-line2—> major trait—>next tier—>major trait…
toughness

or just

power—->tier1—>power—>tier2…
minor trait—>tier1—>minor trait—>tier2…
major trait—>tier1—>major trait—>tier2…

then super trait…and super trait line…

separating trait lines and trait abilities helps create more specific builds and adds more build diversity.