Add a New Cost Per Click Parameter :)
It would be game changing if a new parameter was added that would track cost(one of these: https://advertise.bingads.microsoft.com/en-us/blog/post/march-2016/new-tracking-parameters-for-urls-in-bing-ads) This would give the capability to pass a cost parameter that would pass the price of each click to a tracker.
This would then give me and many others so much more flexibility. In my tracker, I can now see the conversions & revenue I get for each keyword, campaign, ad group, ad, etc, from other parameters, but with this feature I would then be able to see the profitability of each of those since the cost would be shown as well. Right now since the cost can't go through the tracker, I have to compare everything manually in Excel, which is extremely inefficient when you have thousands of keywords, and hundreds of ad groups.