Hey, I seem a little late to the party as well, just wanted to get the discussion going a bit and (hopefully) pick up some tips.
Here's my musings from my experience on monarch.
I play the "Civilizations in abundance" mod btw, so there's a few discrepancies.
Completed, trivial:
Egypt //Never failed with egypt, popping the GA with music was just too easy. Nobody to content with, except the barbs later on.
Completed, Easy:
Netherlands //just not that much challenge here, except getting those plantations up in time
France //I lost notre dame once, but fairly easy other than that, thanks to the UU
Babylon //not too hard, never got beat to monarchy thankfully
Sumeria //beat to alphabet once, otherwise fairly reliable
Portugal // Failed the map goal once, but the extra civs in this mod makes open borders a snap.
Completed, Medium:
Maya //Failed 3-4 times, managed to get both the temple and the calendar. The rest was just waiting, and getting optics to ignore conquerors.
Persia //Wonderfully fun (28'000 score or so)
Rome //barely won, by the end my entire empire consisted of my capital, thanks to civil war :S
Russia // the science goal requires a small territory, so it didn't feel very russian.
Japan //Only made the science goal by building the internet, close game for me. Probably shoulda taken korea, rather than just vassilizing them.
Completed, Hard:
Carthage //almost failed, die is difficult, empire is tough to defend, barely managed to circumnavigate with my stability almost at -50 and civil war imminent.
Having trouble with all the other though, especially (duh) Ethiopia. With byzantium as a proper civ, cristianity is found before I even start half the time (and I dont want to do any egypt prophet feeding or stuff like that).
With the kemer, I can never get the 30% buddism score, do temples/monestaries increase this?
cheers
Derrick