Right now a new player will never understand spell slots and spells per day rules with the current spell UI. Not to mention up-casting lower level spells. There is no indication of how many spell slots you have left (maybe the small number at the button of the icon like we had in the old BG games?), there is no tool-tip that explains up-casting.
I would suggest looking at the mini spell book they did in the Neverwinter Nights 2 game.
Also a character should have a more clear concentration indication. When concentration breaks the game should tell you "[character name] concentration on: Hex, was broken" for example.
The in game icons are so tiny and it's really hard to understand what is going on. And when you put the mouse on the icon you don't really get information about the condition.
