The speed and damage debuff you get for using it on horseback makes it much less powerful than other cavalry classes. Forget about being a class, it's a trinket and nothing more.
Compared to 1h cavalry the additional reach you get using these 2h weapons really does set you at an advantage, numerous times while using longswords / hbs in battle and on the duel server i have been able to outreach 1h cav with the thrust - in that sense it has certain advantages over 1h cav.
In relation to lancer cav the reduction received is the same debuff you get using a lance with a shield from horseback as well. In comparison its really not that bad considering the higher pierce damage of the morning star compared to other weapons usable from horseback (polearm and 1h).
Would you say the damage and speed was justifiable when it received crush through from horseback or was that op? Is the damage and speed from horseback now ok or is it too 'nerfed' to be viable?
Also does the greater abilities of 2h on foot make up for the supposed inefficiency of 2h on horseback? Does this ultimately make it a more versatile class form than a generic 2h or 1h cavalry, to which you should compare?
Although morningstar is somewhat effective, not having a thrust attack puts you at a big disadvantage against other cav and any infantry with a long thrust attack (1h/2h swords)
Indeed the lack of thrust on he morning star makes attacking aware players at speed a suicide, and trying fight (good) lancer cav a nightmare. Remember however that there are several 2h weapons that do have thrusts on horseback and they are more than effective. Against 1h cavalry I've rarely felt i was at a huge disadvantage while using the morning star.