I think allowing players to respec individual masteries instead of entire trees would be a great quality of life improvement for the player base.
Current solution is not only expensive, but also quite time consuming. I understand that it was probably designed in that way to stop players from changing their masteries very often, but the game has evolved so much over the years. In some cases players need to do that in order to go through various game modes efficiently. Hopefully there is something that the devs are planning here

Being able to change individual masteries would be the ideal solution, but if that's not possible perhaps mastery presets are an option?
Devs please... Pretty please