Sub-sections are always good for the currently popular and on-going series, particularly those weekly series (and some monthly series as well) which will attract discussion. Instead of having threads posted and scattered all over the various sections, individualised sections will be more structured and organised, and will look neater.
Additionally, people come to an anime/manga forum mainly for discussion. If they can't find what they want or like, they will not stay. Or put it in another way, if a forum has nothing much to offer, it has no meaning for people to stay.
Obviously, this is only a suggestion. It's up to the owner to decide what he/she wants for his/her forum.
By the way, I don't seem to find many of the bb codes that MyBB is offering. Perhaps the IT personnel should consider the plugins and addons.
All the best to your forum!
:happy3: