I have a idea: At Voobly you can see a time line. You can easily see WHEN you researched WHICH tech at WHAT point in time. It would be nice if we can also see this at DE.
It was much more easy at Voobly to spot your bad researches of techs at that time line than now at DE. I really dont know how to find these stats easily. Only thing i can think of is to watch the replay and hope you see the message…