What if instead of each vault hunter having three distinct skill trees each vault hunter instead got one unique skill tree directly linked to their action skill. Then for your other two skill trees players would be able to pick 2 form a variety of different skill trees (let’s say 10 different ones for now). Each of these skill trees would be fully fleshed out have their own powerful capstones and be centered around a certain theme or playstyles form sniping to grenades or melee, except there would be no direct connections to specific actions skills, this would allow players to be able to use the vault hunter/action skill they like while allowing them to have more customization unique builds and have access to the playstyle they like.
Hypothetical
You like sniping but you don’t like deception, with this system you could instead you pick maya for her phaselock and she will automatically have a tree centered around phase lock and such, then you look through the list of possible other trees and you pick out and tree for sniping/long range combat and a tree for team healing or something else that fits your playstyle
If you like this idea feedback and ideas would be much appreciated, and if you want please do brianstorm ideas for the 10 (or more!) skill trees that players could choose from