Aghanim should honestly be a Rubick Persona. I know a ton of people would rather have him as a new hero but lore-wise, knowing how strong he was in his own labyrinth, why would be be weaker? There’s already a lot of confusing plot lines in the lore and if you say he was stripped of his power and decided to fight in the Ancient war... that’s Zeus’ lore and it’d seem repetitive. And don’t get me started on making him the new Roshan, honestly the worst idea I’ve ever heard.
Having him as a persona would bring better ties as father and son because most voice lines towards Rubick is mostly taunting him for being his father’s shadow. It’d be really fun to see Aghanim side and what he brings to the table. (Plus Rubick’s spell steal is almost exactly like his father’s spell lock)