Hi,
We do see the need to be able to see the sales per months and also think it is a fundamental requirement, and that's why is has been the first thing added with graph displays.
Between a sales monthly report in graph and in listing form, the only difference is that you have to hover on the graph points to see the values, but you already have a quick, at a glance view, of how the shop is performing with a graph (I would argue that it is even easier to see the changes between the months with a graph). So there is not much difference in my point of view between what you want and what is there.
Sure we can look at adding that in the future.