I don't imagine that the current alpha toolbar is anything like the final version: it just looks so sad and lonely stuck in the middle of a widescreen monitor. At the very least I would expect to be able to stretch it horizontally to fit more slots in. Whether that will provide enough slots to be able to fit everything in without having to create a multiple quickbar mechanism is yet to be seen.
A strategic decision for a player character is whether to focus on breadth or depth of skills and/or spells. Do I invest points in many spell groups in order to have a range of tactical options, or do I focus on a small number of more powerful spells? Artificially stopping me from using a wider range of options is blocking me from making use of that choice. Doing so by nerfing the GUI, rather than by a proper gameplay mechanic, is surely just defining the first "essential mod that should have been in the game from the start".
That's exactly what I've been trying to say here, thanks.