I think at least some illusion of choice customization would be great.

Like each class can offer 3 extra abilities and 2 extra traits. each ability
and trait could be upped to three tiers, but you can only make 5 choices.
Meaning you could open all 5 things, or ehances some and not open the others.

Gives a wide enough margin that people can be different, but overall difference
is not that significant.