I'm a long-time Dota fan (since the first game came out as a Warcraft fan-made custom game).
The series adaptation missed all the key aspects that real Dota fans are looking for: their favorite heros and the unique hero spells - that is what Dota is!
In the series, you get a small handful of recognizable characters shoved in to a run-of-the-mill fantasy plot. It really has nothing to do with the original Dota content and shouldn't be branded as such.
False advertising, in my opinion.