So when did this turn into the Team Fortress 2 thread?
The current gimmick is achievements with unlockable features. I won't be surprised if DotA-2 has these, and if it does they would probably take the form of unlockable heroes.
It would not be like Dota to lock heroes away, what they will lock up though is skins or other cosmetics. That is for sure.
They also said you can earn points towards unlockables by coaching other players.
Or by tagging into a game where a player has left. You can earn even more points by doing so and winning the game.
Get ready for a DoTA game with conditional critical and items that don't supply crits but give some other fantastic ability so that makes them balanced.
There are already like 4 or 5 items in Dota that spit out crits. They arn't going to pull those away from you. Especially with IceFrog directing this and especially considering this hinges somewhat on being an eSport. IceFrog would never let Valve do this, have you seen how much he does in each Dota: AllStars patch? He's crazy dedicated to this game.
Every item that's in Dota2 is going to be the exact same as in Dota: AllStars. They have to be if they're holding a one-million-dollar tournament for the thing. If they drastically changed items they would alienate the entire fanbase. Most heroes rely on a certain 'build' of items for their character to work competitively.
This game is not team fortress 2. You don't get negative stats on items to 'balance' items out. The two exceptions are Mask of Madness, and Armlet of Mordiggian, but the downsides are on the active abilities on those items, not the items themselves.
You brought up grind related rewards; achievements are the same concept.
Speaking of Achievements, there is no-doubt there will be progressive achievements. I doubt they will tie them to any in-game reward.