Whatever the number of marks and timing I think students need to learn to pro rata against time available.
On history exam questions, my understanding is that the marks are not just per point made, whether that's 4 or 16. DS2's Edexcel paper has questions for 4, 8 and 16 marks. I've borrowed a textbook from the library for one new module (Migration) which I think is really useful because it gives examples for short and long questions of what's a basic answer - fine as far as it goes - and what's a really good answer, and it should be possible to get all the marks for the 4 marker questions if a student understands what is being asked for and is able to apply their understanding of questions, extracts from sources and what they've revised.
A 4 mark question needs two main points not 4, but they need to be developed. 4 correct undeveloped points would probably still get two marks.
For example - Describe two features of discrimination faced by the Caribbean community during the 1950s.
Black people faced discrimination in employment.
Black people faced problems with housing.
This is a basic answer - it mentions two "features of discrimination" but it doesn't "describe" them or expand at all.
A good answer
Black people faced discrimination in employment. Black employees were paid less than white people for doing the same job.
Housing: discrimination in housing, example by landlords putting signs up saying No Blacks.
So there are two points, both very briefly developed - features of discrimination are described with examples. The answers are still only two or three sentences, but that answers the question.
If a question carries half the marks on the paper it needs half the writing time, but 16 marks probably doesn't mean 16 points, it means a number of points which are each briefly developed and answer the question being asked.