First things first, I think knights should be a special choice (unless army is led by a grand master, then 1+ core) base strength of 4, and inner circle should be 0-1 rare (1+ special of same order if GM is your general) and should have 2 attacks, carry a 75pt banner...
To go along with this we should be able to create our own orders... there is all this fluff about the many different orders in the empire and the differences between them, they should have rules. it would almost be like the sacred spawnings for the lizardmen, so units and characters that lead them would all be the same and same order and rules... This wouldnt be any crazy upgrades that would bring them to the level of chosen chaos or blood knights, more of a way to distinguish them and their weopons from one another... I dont have any specific upgrade ideas or point costs at the moment, so lets come up with some!!!
Also, Pistoliers and outriders should be a core choice rather than special...