I think it's just highest total wins and not how successful you are with them. Could that be right?
I believe it lists in order of most total wins with a specific hero rather than the win/loss ratio(win rate) of a hero. Its kind of understandable that its done this way if you think about it. If you random a hero 4 times and win 3 of those games you have a 3:1 (75%) win rate but if you play a hero 100 times and win 60 of those games (3:2 or 60% win rate). I would say that latter is your more successful hero as you have won more games with that hero even though your win rate is technically lower.
cue everyone arguing me relenting buying wards and courier (then chucking an almighty expletive laden strop about Meepo having to support
) we had no vision for ages as I refused to support all game but luckily their team fight was worse than ours. I keeper dying setting the team fight up which was hugely irritating but we won in the end after I started snowballing. 3rd was equally as horrific with WD refusing to support and expecting me as BH to do it, he got short shrift and the team would not team fight we had a load if wannabe solo winners but luckily they sucked so despite if dragging on for 20mins too long we won.