In my opinion, Divine Soul Sorcerer is limited in number of spells they can know. It is a sorcerer, you choose a few spells from a very extensive spell list, but then you are stuck with them.

Cleric/Wizard with access to all levels is the ultimate Swiss knife of casters. You can prepare any cleric/wizard you want. That is why it would be more broken if 1 level of wizard allows casting higher wizard spells.