I personally ended up building some custom Markov Chain Monte Carlo models (because with the Steam API you can pull a lot of match data) with shared priors just to understand the farming/win relationship per hero (and you need hierarchical Bayesian models because with 100+ heroes, 10 heroes per game, and needing to account for between-hero relationships, you run into the curse of dimensionality quickly).
It's almost more fun to analyze DotA computationally and watch tournaments than to play it (I watch more than I play). That's a truly ridiculous skill space and I could probably do an entire PhD's worth of statistics mining just off DotA 2.
Have you played Brogue? That is really something special. It's a really stripped down game inspired by the original Rogue. There are no classes, so your build depends on the items you find. Rather than experience points, you'll find a finite number of scrolls of enchantment to spend on items. The tight food supply forces you to descend, which in turn prevents you from saving scrolls of enchantment for too long because you'll need to spend them on your items to survive. But the longer you can delay the better, because if possible you want to spend them on top-tier items.
Almost all of those things are examples of a game (DotA 2) being hard in a bad way/for the wrong reasons. The hallmark of game design is that it should be easy to learn but hard to master, but DotA games are notoriously hard to get into because of the steep learning curve, mostly because of all the dozens (almost 100?) heroes', their abilities and all the items (some of which have active/spell abilities) that you have to learn. I was useless in all of the initial games that I played in HoN, even though I had friends to help me. I still get bitten in the ass by not knowing all the abilities of some hero, or the fact that he has some item that totally negates one of my heroes strengths.
Strategy games of any interesting complexity usually have a steep initial learning curve, where you'll fuck up everything in the beginning and/or get killed by overlooking one single aspect of your base management or army control. But DotA is astonishing in that it was created in a game where you have to control up to three heroes, an army and base management, simplified it down to controlling only one hero - and made the initial learning curve of the game harder than the original game (Warcraft 3)! And this custom game with the higher barrier to entry in the end eclipsed Warcraft 3 itself when it comes to popularity!