I'm currently in the process of trying out different builds before starting the game and this is one thing that is badly needed. Pretty much every modern CRPG (and some older ones) I've played have this. Pathfinder, Pillars, Tyranny, Solasta, just to name some of the most recent ones I've played.
I'm fairly familiar with D&D 5e, so some of this doesn't affect me, but with the attention this game is getting, it's sure to attract some new players to the CRPG genre and they might be frustrated by this.
I would also like to be able to save a characters without having to start a game.