The powerful cards add something to Dominion that previous expansions have lacked, and that adds something that really pops. I'm not quite convinced that province-collectors can compete with colony-collectors in the same game, so the strategic space hasn't exactly doubled, but the variety certainly has.
Very nice map for RR Tycoon. The game is both financially and geographically tighter, and the map is has a color structure, with red cities in the middle, and yellow and purple cities at the perimeter, to encourage building from center to edge. On the downside, this did create less differentiation among play, making it more about competing at parallel tasks. RoE forces balance and competition, where RRT expects the players to provide it through intelligent play and bidding.
I'm rating this below RRT for a couple reasons: It lacks some of the grandeur of the original map, and fails to bring any exciting innovations to the game, as opposed to cool rules in several BGGer-made maps.
It's nice to have a more expensive map that takes 5-6 players. The shorter game length (due to fewer cubes on the map) changes the debt dynamic to compensate, too. My one complaint is that the plethora of mountains (even in places where the land is rough but flat) limits the number of smart routes, such that the Rockies and coast might as well be a point-to-point grid, and the plains seem too poor to compete.
This is offset by the ability to put the eastern, western, and/or Mexican maps together for mega-games.