I know a lot of people hate the term E-sport... and I tend to agree with them, but Dota 2 does works a lot like a sport
Well, there is strategy, tactics, fast reaction, a lot of decision making in real time, team work, in dota 2, and as any sport dota 2 have a learning curve, you need to understand first the rules of the game, then when you got them all, you have to understand the basic reasoning behind the game actions, why those guys are killing me everytime when im in my jungle?? - is probably because they have wards in it, wtf is a support, carry, ganker, initiator??? there are a lot of questions in your mind when you start to play the game, and there are a lot of frustration too, the best advice I can give to anyone who really wants to experience the game is, go with a friend that knows the game on every match, he must pattience and be ready to learn and ask a lot of stupid question, because you will have them.
with practice (as any sport) you will start to get the feeling of all those things, Dota 2 is a very complex game, but is a very fun one to experience, and you will have a lot of endorfine onces you get it, and start to win games, you will learn how the heroes works, wich items are good for you in a determinated situation, which other heroes have synergies with yours at the end, the objetive of the game is to play with other 4 guys, and when you start to get your role on the battlefield, you will be pretty satisfied... is a very rewarding game, and addictive one for that matter, but be prepared, if you want to really get good at this game, you will need to play, and to play a lot, im talking about 600 hours, to know the game mecanichs and all the important stuff.
So dota 2 what it needs is that you have the time to play it long enough, and then you will see why is so good, and dont forget is free, and you have access to all the heroes roster from the start.