Honestly, the only thing I could see being added to Sarleon is armored footmen having a higher chance of spawning with shields, and some kind of levy horseman.
The shields are easy to explain, but as for the levy horseman I would prefer to see then different from either D'shar dervishes or Ravenstern horsemen. To that end, I would style them on knights of the lion: single handed melee weapon, shield, light lance, either footman or armored footman equivalent armor, and a hunter or saddle horse.
That would be my solution, they are not as good as Ravenstern horsement (I've seen them spawn with a great lance, and axes) in regards to damage, but they occupy a role as skirmishers/ light calvary.
Although, honestly I'm not sure how Sarleon, the knight faction, didn't get a levy calvary of some sort. On the other hand though, I'm not sure how such levy horsemen could be made unique enough to not just be Sarleonified Ravenstern horsemen/ Empire light Cav.