Having previously helped write complex software for international investment banks, I am acutely aware of what it can be like to work on such projects and the amount of variables that need to be monitored and carefully processed. I attempted to use the available online tools to record my own accounts across various exchanges not so long ago and the results were not impressive at all - partially due to the same problems you highlighted in your post. Any software that carefully solves these challenges is a definite boost to the entire industry of cryptocurrency and I strongly suspect you will have a lot of potential buyers if you do offer the code as a product for wider use. :)