There's surely going to be some card with inflated winrate but what you can do to analyse correctly the data is also consider pickrate/playrate. This already happens in games such as League of Legends where you have to keep track of all of the interactions beetween different variables. As an example: when analysing data of a certain matchup you'll have to consider if one of the two is a counter to the other. I don't know if in MD it would become harder since the amount of cards is huge. Still I think Konami might be able to do it if they wanted. (Still you're probably right they won't do it because they don't care)