There's a point, though, where the user interface gets in the way of enjoying the game. It's fine if the core mechanics are complex but they should be exposed to the player in an intuitive, accessible way.
I figured out most these old games between the ages of 8-12. If you can't figure out how to use arrow keys or read the quick start guide, I'm not sure you're in for a future of even flipping patties, much less doing anything other than mashing buttons on your console controller. I know Ultima using the entire keyboard is seemingly too much for a modern "gamer".