Pie charts probably aren't on the way but as I mentioned here you will have access to more comparison tools soon -
That sounds pretty handy though, is there any chance you could share a screenshot?
That screenshot's taken from an iPhone (which I use too). The comparison with the average spending has gone now but if you top up the same amounts each month, at roughly the same time, you can use the pulse graph (also explained in the blog post) to compare your spend at this point in the month with previous months. According to the roadmap, that'll be ready for Android users too
Lastly just to mention, there is an option to export data into a spreadsheet for more analysis which is on it's way for Android as well.