Very good point; with "flexible" rules for light cavalry, one should be able to mimic many historical options. The idea of course was to use Marauder Cavalry as the closest unit of comparison. While Reiters would have more weapon options, the Marauders still have better Weapon Skill and Initiative, Marks, Horselords, and Will of Chaos, so it should balance out roughly.
I will probably rewrite my suggestions for Knights, Outriders, and other stuff later on.