2. How often you interact with that system depends on the genre of the game.
(For example: if you get ambushed by gunmen in a John Woo movie, you might end up fighting for half hour and live and then get in three more fights later, if you get ambushed in The Godfather you are going to die in the next minute, period, and it will probably be the only time you fight. If you get ambushed in a Lovecraft story you will probably not only die immediately but it's the only violence in the whole story.)
3. Therefore different genres need systems of differing complexity.
4. Games which typically spawn the longest-running campaigns embrace the largest variety of genres and subgenres (to keep the game interesting over time).
5. Therefore different systems of different levels of complexity are desirable for campaign-style games.
6. So shut up about how great it is that your game uses the same engine for everything.
In other news: Red & Pleasant Land is a finalist for the Three Castles award along with some other good-looking game stuff. It looks like a pretty nice crop this year so I'll be happy no matter who wins.