Separate leveling imbalances the game to the point that i sometimes have no clue why my team looses or wins. I'm sure when I power and elo my way up to where everyone is more even this problem will go away but till then its all up to the matchmaker.
I can't find any of the actual math so a third of my build decisions are complete guesses. Even if this gets solved item transfer penalties strongly penalize testing builds out.
MMORPG grind and Browser Strategy grind hooks. Never play to gain in-game power rather than immediate fun.
No dominion mode, so old rage problems exacerbated by mmorpg leveling and bad matchmaker.
I wish they spent less time on the minigame and castle building and more time on actual game.
The gender system. Ehhh.
Pacing in game with the tactical combat not ending in one second and the strategic pauses not taking too long.
Separate hero Elos.
Voice acting & art.
Awards and rewards based on ingame performance. Something to work for even if you know you will loose.
There are a bunch more modes but most are only modifiers.
You will know to stop playing dota when you team does better if you minigame instead of teamfight.
The game gives best items when player spectacularly looses in pvp. Lol
One of the few games i can see enough to play on my shitty monitor.