Most of my comments were directed towards Diablo 2 within a year of 2001. I think that Diablo 2 was accidentally a much better game than they had intended it to be. Every change they have made since 2001, aside from patching cheats and exploits, has been for the worse.
Unfortunately, I think this will continue through to Diablo 3. Blizzard wants people hooked into the storyline, leveling, and questing. They don't want you doing anything that puts unintelligent players at a significant disadvantage, and they don't want anyone profiting. In my opinion, Blizzard has adopted a real fun-killing control freak attitude, geared towards those who live more in fantasy than reality, and are sensitive about possibly having their little fantasy world disturbed.
Diablo 2, at its best, was 60% trading, 30% dueling, 10% questing/regular gameplay. I'm sure Blizzard will force Diablo 3 players to use their stupid game in the one way they see it should be used. For me, no freedom means no fun. And many of the changes I could see from the video just indicate a decreased level of player freedom. For instance, by replacing potions with healing orbs dropped by monsters, etc.