It seems to me the campaign is really an extended tutorial but I'm still enjoying it even though I can't seem to beat the civil war ep 4 yet.
JZ,
I haven't tried the sandbox or free modes but I don't think the maps are big enough and the time limits too short (they make you stick to a single era) to make either a great long term game.
I am[/] hoping that by giving them my $50, something I rarely do, that I am on the encouraging end to get some DLC made. I'm liking a lot about the game. I'd like more though in all honesty, there may be more. Commerce may get more complex once I finish the campaign and see what else the game has to offer.