There is also the Quick Switch talent that helps you switch grimoires faster. What I like to do with Aloth (or with any wizard really) is have a damage book, a melee book, and a control book. Most of the time I use Wizards for control but when I feel like mixing it up I bust out the melee grimoire and go to town. What I've found is in this game the companions may not have optimal attributes for say PotD but they are well rounded for the other difficulties. I've played with Durance in scale armor with a sword using his Magran talent. No shield, just a sword and he does great.