Among the goodies I've considered for progressively higher wizardry talents:
- Gradually increased Staff Mana and other Staff properties -- obviating any need for multiple Staff spells or purchasing Staff mana with XP (each talent is purchased instead, maintaining balance while simplifying rules
- Enchantment itself becomes one of the highest talents -- thus replacing the magic item creation spells
- Automatic spells (perhaps one per advanced talent) such as Mage Sight and Analyze Magic that the wizard can activate at will, at any time, without a roll and without using their action for the Turn
- Exclusive access to higher level spells
- Expertise in one type of spell (perhaps +1 or +2 DX) for (T)hrown spells or maybe another class
The Sorcerer's Tongue (or your local campaign world's equivalent) ought to be the prerequisite for the first wizardry talent. At least in my world all spell invocations/incantations whether verbal or mental had to be in our magical language, or the sign language equivalent. Although a feature of this rule is that a non-wizard who speaks the language has a very good idea what spell a wizard is casting when they hear the incantation. We also had a rule you couldn't tell a lie in this language, but that might make play over-complicated.
I'm still on the fence about whether Literacy must be a prerequisite for wizardry talents (some, all, or none?)