I do wonder if the sorcerer can swap out every night (long rest) doesn’t that make them MORE versatile then the wizard who can’t swap spells in his book??
Example: playing a 3rd level wizard and a 3rd level sorcerer neither knows knock... only one can learn it over the extended rest...and it isn’t the one we think of as versatile
It would if they had the same spell list. They don't. The Sorcerer spell list is significantly smaller than the Wizard's. On top of that they have noticeably fewer spells known than a Wizard does spells prepared. If it really bothers you, I can see ruling that only the PHB spells are freely accessible and spells from supplements need an OK to be allowed. But I highly doubt it's necessary.