I agree with your assessment. The game, without the challenges, is a little to simplistic...it would be nice to see an expansion with more complicated moves, and perhaps more tiles and new pieces, such as trees, fountains...[just spit balling here], etc, to make this game more memorable. I see a lot of potential.
Looks neat. I would probably always play with the rule cards. I am curious if it would effect the game too much to have more than one of those cards in play at a time.
I wonder how publishers feel when a designer uses a very similar mechanic in two games from different publishers relatively close in time. Like, these bridges are very clearly similar to the monorails in Barenpark. When working and pitching these designs to publishers, does he have to disclose that he will be publishing a similar mechanic somewhere else? They reasonably could eat into each other's sales. Like I don't need two mono rail/bridge games. I would just get the Barenpark expansion and skip this.