But it is something that should be expected of them to learn, since it is a role in the real game, no? Is there a reason I'm unaware of that would be a reason smite wouldn't be available from the start? It's not like it'd break the game for newer players to have it, even if they don't get the concept of using it in a particular role.
I think overloading players with a lot of things to learn is a fast way to overwhelm and potentially scare them off. Slowly trickling new mechanics in is a much safer way of doing it, which I believe is the approach here.