Don't follow Dota or play it but have been watching The International just due to money and coverage. Like a casual soccer fan watches the World Cup. Game is way too complex for me though, but, I get at least some of the concepts.
Have you been watching the newcomer stream? They try to explain everything as though it's the viewer's first time with the game, explaining hero abilities, items, and a bit of the decision making process. Watching the runup to the first International was how I got into Dota, back when they were doing that for every stream.