We already have tutorials, and even a graphical one from the moment a new player signs up. Even with all the added complexities, for most new players, the standard set of actions remains to get an oath, set the estate, get a unit, set their behavior, and move places. Anything beyond that is really up to the player to find out.
It might happen that some players on't find that much interest and don't look further, but it is also time-consuming and difficult to provide in-depth lessons. It is also hard to make them have any flavor as a mentor and not seem like textbook passages. But when we think about it, this game is about fighting each other so at the core, what we primarily do is in fact recruit units and move around to beat other realms. The rest is more or less embellishment which adds some deeper complexity to the fighting.