Anyway, a challenge is mostly a plus for me. And as I said, the only challenge I want really is that I have to watch the money a bit.
Their last game, CiM2, was a bit too stingy (at some point I just pressed the "unlimited money" button and then only looked that what I built was profitable after a while), so who knows whether they overcompensated. Anyway, there's everything there from hard mode to unlimited money, and you can probably mod the hard mode further.
If this kind of games is too stingy with their money, they tend to funnel you into a very narrow path to success, which means that you may have to follow a very repetitive style of play. You get some variance from different terrain layout and resources, but there may then be
one superior layout and
one superior sequence of zoning and plopping down buildings. At the moment you figured this out, and with the game being unforgiving of other approaches, it's basically dead at that point. So I prefer some leeway here.