If I were to make a mod, it would be inspired by the
Classes Combined mod, which is a lot of fun but a little overwhelming. I'd love to see similar classes combined - mainly their passives - but done through the lens of being a specific gods champion/chosen. Where "Chosen" would be the class and each Deity would be a subclass. Examples:
Shar: Combining Rogues, Gloom Stalker, Shadow Monk.
Mystra: All the Wizard subclasses, Eldritch Knights, Arcane Trickster.
Talos: Storm and Lightning Draconic Sorc, Tempest Cleric..
I'd also want to consolidate/combine similar or duplicate abilities for QoL and cleanliness sake.