I think the sword cavalry fills a good gap between knights and full cavalry, the heavy horseman would make a good filler between the horseman and knight- A heavy knight and crusader would be good for scenarios, such as the rise of Islam, the crusades and the eruption of the mongols and Vikings- all very popular scenarios.
I tend to do whatever unit feels most fun/ challenging at the time; ballenced by how usefull it will be. Sometimes its purely about the fact that I'm tired of doing a particular kind of unit like tanks for example. Eventualy they will all get done, but for now I'm interested in getting some early industrial units finished for perhaps doing a scenario. I will do the heavy bomber and the tank killer etc.. but at the moment, I am exited by the challenge of doing a cavalry model. Next will be a imperial (bayonet armed)musketman, who could be used as a redcoat (given a red coat) or as any other kind of musket unit. The british army uniform went through so many cahnges, its realy hard to cose one for use- the helmet on the unit I originaly posted (when i corect the shape) will realy mark him out as a british soldier, but then thats all he can be used for. I'm thinking of using a more generic shaped hat, (as shown at the bottom of this post) similar to that used by man infantry armies between the fassion for ticornered hats and the adoption of the flat cap (like in "north" american armed forces during Civil war) and the various helmet designs adopted by different nations.
Ive only got the death animation to do on the sword armed horseman, I'm quite happy with the rest, not as smooth as the firaxis units but very reasonable.
Here is a picture of what the generic early rifleman may looklike, Iv'e just changed the hat, need more research in to the actual design, and I can't help but feel that he looks a but too burly for napoleonic infantry, perhaps his shoulders are too broad? Any way the whole model need some work- I think I'll work on the Super ironclad and some Frankish style heavy horsemen next.