Reply: the unsaid things were Gospel mysteries the disciples could not yet bear
The many things of John 16 are not a blank check for later Roman traditions.
They mean the clear unpacking of Gospel mysteries the disciples could not yet carry.
Cross, resurrection, ascension, session, Gentile call, end of legal worship, New-Testament church — Christ had sketched these briefly.
Prejudice, grief, and the still-missing Spirit blocked full grasp before the Passion.
Latin
III. Respondeo per multa illa quae testatur Christus se dicenda discipulis habuisse, & quae tamen discipuli ante Christi mortem portare non poterant, intelligi accuratam & distinctam explicationem mysteriorum Evangelicorum, veluti de efficacia & fructu mortis Christi, de resurrectione illius, de ascensione in caelum, & sessione ad dexteram Patris, de vocatione Gentium, & cultus legalis abrogatione, de statu Ecclesiae sub Novo Testamento, aliisque hujusmodi, de quibus quidem breviter & generatim Christus discipulis locutus est, etiam ante mortem; sed ea tamen tunc illi intelligere non poterant, nec eorum accuratam explicationem ferre, propter varia praejudicia quibus mens eorum erat occupata, & tristitiam summam qua dejectus erat illorum animus, & quia nondum acceperant illum veritatis Spiritum qui mentis ipsorum oculos erat illuminaturus, ut Evangelii lucem ferre & aspicere possent.