Let us level up our weapon mastery to 40 and unlock all skills and perks with one weapon and let us use all six skills for that weapon, rather than letting us use three skills with two different weapons.
This would balance out any issues with the rapier for instance, you wouldn’t get a free escape and then heal yourself to full with life staff. Only players who actually ran rapier could use those tools to escape but ALSO those players would get to make use of the interesting tools on the left side of the tree too. Every single weapon in the game has the potential to be extremely powerful on its own but with weaknesses, for example every class in the game benefits from using rapier to run away but if you are locked into using just the rapier than its balanced with the fact that the only way for you to get value out of this weapon is to use it offensively.
I think every weapon in the game right now is powerful in its own right if you have access to all six talents without being broken or overpowered.
For example void gauntlet was overpowered when you could scream and one shot players with ice spike, but making it so that you could only equip one of these weapons would limit people from abusing these types of mechanics.