With Hogwarts being remodeled, perhaps they have gone to a new teaching structure as well.<br/><br/>In an attempt to give the students more "one on one" they have brought in teachers to assist the main professors in the instruction of the students.  That means the professors of the more obscure electives could assist in the main classes, gives tips to students, and add another pair of adult eyes in the classroom to prevent certain student shenanigans.<br/><br/>McConagal (sp?) always seemed much more strict than Dumbledore after all.