any reason why was everything pluralized?
Because Gouru wanted to? :) Perhaps to more correct, there is more then one tusker in AC.
A lot of the plural names are not correct. These creatures are the same word singular and plural: Burun (and classes), chittick, carenzi, Mukkir, Niffis, Olthoi, Ruschk, Siraluun, Slithis, Ursuin, and Virindi
The Human groups Raven Hand, Tanada, and Zharalim are not creatures, but groups, and dont need to be pluralized. The Word Undead is plural, along with the three groups below it.
And Sclavus is Sclavi, not Sclavuses...
nevermind, I see there is a forum now, and Gouru posted an explanation:
The posting of the monster 'Skeleton' I realized would have clashing page names as the monster class and monster itself had the same name.
I considered a couple solutions, but in the end decided to use the plural form of the name for class names, with the monster name itself being the singular.
I did a mass cleanup of the monster section to implement this change, and modified the template to match.
I think you should change them back, or at least, correct the plural names. As far as I know there are very few creatures that even share the name of their creature type: skeleton, undead, cow, and maybe a ghost. And these few cases could be dealt with by simply titling the entry Skeleton (creature)