If you take care of your units they can remain valuable in the late game. All units are properly themed to the champion. For example Drogon has a Dwarven Friar with a unique heal spell and a improved wolf cub who is fast and hard to hit. The ranger has a druid spirit bear, with howl and a fear ability and a Ranger apprentice Harton who can disable and opponents.
CAUTION, these files are meant to be dropped in the C:\Program Files (x86)\Steam\SteamApps\common\Sorcerer King\data\English directory. They will OVERWRITE the ones already there. Make a BACK UP of the 4 corresponding files in the zip file BEFORE overwriting them. As far as I know there is no mod directory to make this easier as of yet.
Enjoy, and leave a comment if it does not work. I will mod the other two champions in a few days.