Have you played BG1/BG2? In most cases you didn't have anything to say during levelling up. From time to time, you could add weapon master point to the weapon or spend attribute points on thief, but that's all
I think this won't be an issue once you can multiclass. This will open up a much more interesting way to play each character. Its only a matter of time before it gets implemented.
Strongly disagree. The game should be accurate to source material. Some classes don't get anything beyond more hit points upon leveling, and that's okay.