JConstantine
Working-class warlock
I could see something like a cross between 5e's feats, 3e's feats and Savage Worlds' edges. So, using 5e as a base of comparison, instead of2. A half-dozen "core classes" with feat trees, to replace the 13 classes/900 subclasses/multiclassing system.
Class feature @ X level
Subclass feature @ Y level
ASI/Feat @ Z level
you could have
Combat feat @ X level
Exploration feat @ Y level
Social feat @ Z level
Some could be general and open to all, while others are restricted by class or species, etc.