My decision making has also improved from Diretide. My last hitting needs some refining but I feel like my ability to pick fights correctly and work with my team really increased in the last week.
On the heroes discussion, I've played every hero a handful of times each. I'm not a "main character" type, though I do gravitate towards heroes that I think can be real game-winners like Lion and Leshrac. Also lots of games as Windrunner. Very few games as boring agi carries like Sniper, BS or Juggernaut.
Speaking of heroes, is there a good list of what heroes are good counter picks to others? Like a chart of some sort? If not it would be a good project to undertake.