5th dnd – Balance problems for a custom sorcerer variant in D & D 5th

I have recently started reading Terry Brooks' Shanarra books and this has led me to think about how the concept of wishsong could translate into a system like d & d. My (very) approximate idea at the moment is a subclass of wizards that can learn spells from any school or class provided that this spell uses ONLY verbal components.

I found a very good tool here: http://donjon.bin.sh/5e/spells/ which allows me to filter for a list of all only verbal spells. In terms of levels, the list looks pretty well distributed and shows a decent mix of combat and non-combat spells. That said, I do not have an encyclopedic knowledge of D & D spells and my experiences with the wizarding class are limited. Does anyone know if any of these spells would be seriously unbalanced if it were combined with the class features of a wizard?