I would definitely copy the wow classic system, that's for sure. Trying to boost several viable builds (I know how difficult this is).
But it's great, depending on the type of talents for example, you were a warlock based on your pets, one based on dots or one based on being slower with casts but you do more damage.
I think it's the best, 3 branches of talents, you gain points from x level maybe 10? and from there, you gain one point per level. You distribute it as you like by unlocking skills and so on.
I think that's enough, doing something like path of exiles will only scare away new / intermediate players and it's silly. (In my opinion)
Yes, sir, I think you were confused with what I wanted to mention. He's not talking about talents or about all the skills being acquired from the bosses