I had to log on just to say its not like League of Legends EVEN THOUGH LEAGUE CAME FROM DOTA 1 check -> ttp://en.wikipedia.org/wiki/League_of _Legends<-
Dota 1 came from a map for Warcraft 3 and Dota 2 is only a visual and sound upgrade from Valve engine and the creator of dota 1 the "Icefrog"
Dota has much more complex mechanics since there are items that mimic almost all abilities and also bring additional uses. Not to mention almost any champ can play every role/lane. I will quote the nickname i saw the other day in league of legends champion select "LoLisDota4Kids"
ps: i played dota 1 for 8 years and i think dota 2 is ugly.. only play league of legends because i like cooldown reduction mechanics since i only play mages