On a slightly different point concerning Mods and Steam:
Steam is a pain for this I find. I was forced to download the `No Mechs` mod from Steam (cos I couldn`t find it anywhere else) and now I get the Mod appearing, then it vanishes. I redownload it and it vanishes again after a while!
The Mods I manually installed from this site (civfanatics) and put in the Mod folder have been fine.
Modders need to keep non-Steam versions and not put them all in Steamworks, it`s too restricting.