I think some time limits can punish the people that have revised more than others. Just find it amazing that, for example, GCSE maths exams (where including methods, you write about a page) have the same time periods as A Level History (where you have to write around 7/8 pages). I know in maths you need to read the questions, but you need to read the sources in history?
I think it encourages people to learn answers and fit them in accordingly, rather than answer as you go - which is probably why some examiners have claimed answers are too boring/ formulaic. what do they expect? Some I think need tweaking by half an hour or so.