Wanted to double down on this suggestion.
The ability to "build" your spec in game without spending ability and talent essence until you apply that build would be great.
As a new player, I am unfamiliar with methods for acquiring purges and scrolls of unlearning right now, so I am always worried about misclicking the wrong talent or skill and then having to unlearn.
I would still keep the spec currencies in game, but a builder might help alleviate stress when making new builds and assessing new talents and abilities.
EDIT
Wow, I had no idea you could use the Hero Architect in game to create builds like this. I always thought it was just for publishing your ideas. I learn something new every day
For anyone not aware, there is a create build button on the bottom left of the creator that allows you to freely make a build and just choose it without having to upload it.