I've played Cities and Knights, and I like it a lot better. The progress cards let you affect trade, other players, or speed development, and offer some additional strategy. The aqueduct ability (#3, paper) even minimizes the effect of a dice-induced resource shortage. The constant threat of barbarian invasion always results in a race for knights, and the accompanying strategies of trying to one-up the other guy.
C&K basically gives players more ways to affect the game's outcome through actual decisions (more of which are sorely needed). I haven't played it myself so I can't say how effective they are, but it's a step.
