Aslam-o-Alaikum fellows,
essay is an attempt through which examiner checks student's writting skills and knowledge about the subject.
The writting skills include grammar, sentence formation and infact everything that is part of your piece of writting.
And, the knowledge about the subject include what do you know about the subject?how thoroughly have you studied and absorbed the knowledge of the subject and how well you are aware of the other things which are concerned with the subject ultimately.
So,there should be no criticizm a good essay should be blessed with facts or not.Undoubtedly, it should be blessed with the solid reasons.

Regards

__________________
Baroz-e-Hashar main be-khof ghuss jaonga Jannat mien,
Wahin se aye thay Adam woh meray baap Ka ghar hai
(Allam Iqbal)