No heroes in the multiplayer element because, otherwise, we are looking at a futuristic total conversion for Warcraft III. On the other hand, hero units will be present in the single-player campaign, just like in Starcraft and Brood War.

I like the idea of experience points and unit promotion. It adds an easily manageable element to the game that makes the player care a little more about his or her units.

I have some other concerns about the gameplay and look of the game. Things like combat animations and movements. Why do all the units have to stop moving before firing still? Why do the air units just hover and shoot at each other one at a time? The alternative to this, of course, would be to have them fly around each other and dog fight; C&C does this rather well with the GDI's air units. Also, why does the battlecruiser have just one gun? Granted, I can understand it using one main cannon for air-to-air attacks, but when it is hovering over the battelfield and providing air support for ground troops, it should have some serious bombardment abilities, e.g. several guns blasting the ground around the enemy ground forces.

I've also posted several posts on my blog discussing some various topics surrounding Starcraft II. They are too long for me to repost in this discussion.