Faris and Qatif-al-nar as heroes?

[Gyra_Solune]

One thing I've noted about the Khalifate is that for whatever reason, the Faris and Qatif-al-nar are not able to be chosen as leader units. This strikes me as fairly odd! Not only do they fulfill all the criteria of a 4-6 MP unit with 1 MP cost on land, without any particular abilities like berserk, but in Age of Heroes, their level 3 units, the Mufariq and Tineen are available as heroes despite being more or less the same unit but higher leveled. I personally think these two units should be allowed to fill that role, as there's not really any reason I can think of why they're not. Unless there's some particular reason noted they were excluded?