At first glance, as an avid fan of the first game and a long time real time strategy gamer, i was quite disappointed by the simplifications made in the economic system of the game. It kind of drove me off a wall that the once gloriously complicated economy of SC had been reduced to building three types of buildings.
Then i stopped and gave it a day to fester in the back of my brain.
And then I preordered the game.
I actually pondered the trade-offs of having a more simplified economic structure and a research tree and after thinking about that for a good while, I gave in to the fact that the research tree will produce much more team coordination and that the simplified economy will let me worry more about commanding rather than queuing up my gigantic base of dewm. The early game will be way more fun with the simplified economy than it was before.
I miss the deficit spending that was the hallmark of TA and SC, though. No more can you queue up buildings and build stuff you don't have all the resources for. That was a unique feature that allowed for epic scale...yet it's not needed anymore in SC2 because the way the economy is set up.
If you're a turtler or someone who loved supcom1 and TA's economy, do not waste your time playing with SC2. SC2 sets up to be a very aggressive, fast paced, in your face style of RTS that is going to require macromanagement of your armed forces and micromanagement of your production setup. I think SC2 will more faithfully deliver the "epic" battles that everyone was looking forward to in SC1 because the economy is easier to manage, the units build somewhat faster with experimentals being cheaper and easier to reach, and the game's design allows you to very effectively focus on command.
Supreme Commander 2's UI will be a treat for those of us who disliked SC's UI. The UI is very minimalist but provides the essential information in much better locations than before. Controlling your units is a lot easier - recently produced units out of a factory are all grouped as are recently moved units. This lets you simply click on a group on the strategic map rather than having to click and drag each time. The system lets you have much superior control when micromanaging all of your bazillion troops.
It'll be fun, fast and and furious.