Hello, here is another player of Civ 3, who is very dissapointed about Civ 4 and the way the Civ series is going now.
May be the following link can be of some interest for you:
http://apolyton.net/forums/showthread.php?s=&threadid=169829&perpage=30&pagenumber=2
In that thread I transformed a couple of animated Civ 3 units to animated 24 Bit-BMP-Sprites for "Civ 2 ToT" by using a simple tool, that the modder Mercator offered to the Civ 2 community for free. There are thousands of animated high-class units for Civ 3, that can be used for free by modders (so not for the first commercial release of that game). I was able to do this so only beeing a normal gamer and no graphics artist.
May be you should consider about a simple feature to allow modders to introduce graphics from Civ 3 to this game.
And you should use better terrain graphics.