Highest losses are also in the crosses or minor pairs.
I think it depends on the trader more than it depends on the currency pair. Some of the worst mistakes that I have made happened when I was trading EUR/USD because of how volatile and undecided it tends to be most of the time, and yet EUR/USD is the most popular currency pair. I think it's important to spend time studying any given pair, regardless of how popular it is, to get used to its behaviour before trying to trade it in order to avoid at least some mistakes. That approach can be applied to all pairs with the same success, in my opinion.