I disagree, mrtn. The cavalry units made from cossacks that i have seen so far looks very good, detailed and interesting, as well as personalised details per each different one. If "fixing" them to fit the civ-scale means to lose such graphicals details (like the ones seems on the sweedish hussar or the russian one : detailed different uniforms....) then is not really a very good idea. after all, is the game scale the problem.....just look at a city and an infantry (lets said : rifleman, since i think is the one that taller look), the rifleman looks bigger that the city itself......so, in a case like this....a few extra pixels bigger is no problem if it means more details and richer graphics to each different unit.
The size diference looks kinda weird, true.....but that still happens even with the units that civilization brought from factory (for saying it like that)......
well, thats my point of view. Bottom Line : they should stay on their original size (the one that the cavalry already maked has).