I’m soloing my way through Mage Knight. I like how there’s a lot more going on than “move here, kill monster”. I especially like the mechanic of gaining fame to attract followers, who you need in order to siege towns and fight bigger threats. I think D&D would really be enhanced by this level of strategic gameplay. Domain play becomes more natural when you’re already traveling with a large camp of followers. 

Also, resource management in Mage Knight is more about gaining resources by building them in the world, rather than just buying everything in town then slowly losing them in the game, which is an added level of incentive, I think.