I’d recommend reviewing the available class specialization trees and revising them to include viable talent paths for builds outside of that specialization, if those builds would benefit from a skill within those trees.
My experience is, specifically, this:
I am a spellcasting Mage, specialized into the Sorcerer mastery. I would like to pick up Ice Ward from the Spellblade tree. The only available node with no exclusive-to-melee bonus is Elemental Affinity, which only has 8 points maximum, which means, given my build, the next two points I need to reach Ice Ward give no benefit. The next ten points go into Glacial Might, which is fine, and the last ten go into some combination of Prismatic Blade, Capacitor and Shiver Armor, which grant only part of their bonus.
By comparison, the Sorcerer tree has only a few spell-exclusive talents; a Spellblade putting points into Sorcerer never has to put points into a talent that doesn’t benefit them; the only real worry is which elemental specialization they’d like.
It’s not a huge concern, obviously, but if skills are locked behind talent progression, then giving more viable paths through those trees could open up more possibilities for yadda yadda yeah, you know how game design works. Just think about it, alright?