The main purpose of an ESL composition course is to educate L2 learners in the area of written academic discourse. This can be a very demanding task for the instructor and for the students. There are a number of issues involved in achieving the intended result successfully.
Those who have ever taught an ESL course would agree that you cannot have a completely homogenous group of ESL students in one classroom. Typically ESL classes include students of different ages, genders, personalities, cognitive styles, motivations, socioeconomic status, cultural backgrounds, L1 educational experiences, and different levels of L2 proficiency.