i have two questions though:
1.
in CIV4ArtDefines_Terrain nearly every terrain has a double entry, with something akin to:
ART_DEF_TERRAIN_TUNDRA
and
ART_DEF_TERRAIN_TUNDRA_BM
where the _BM version is just a copy and is not used as far as i can tell. do you know what those entries are there for? i think i have not seen them in earlier versions.
2.
i tried farming land akin to spice used in earlier Dune Wars versions, but it looks as horrible as the spice back then. i think the only really good way to get good looking connected farming land is to make separate terrains for them. graphics wise this would not be a problem, but it may affect gameplay, mostly terraforming spells.
for example, instead of the ugly farms we have now, or even the slightly better looking farms from my post above we could have real farm land like this:
But like i said this would require to switch farms from an improvement to a terrain and i am not so sure what the best gameplay changes would be to do this.
edit: the easiest way would be to keep farms as an improvement (just the little hut without the crop fields) but as long as the farm exists it changes the terrain it is on to farm land. that way the gameplay should not be changed at all. although making farmland a separate terrain type could make for much more interesting gameplay changes.
are those black bars such a big deal to you?