[haro41]

Depth. A system that doesnt require one pass thru. Replay-ability.
An in depth tutorial of how to get started. Where to make money. I want to be impressed from the start. A first impression is key to graal players. The average player has a very short attention spans.

It really doesn't matter what kind of system it has. Any kind can be just as fun as the next.

But personally I'd like to see a well scripted RTS server. That is simple to learn, and maybe even simple to play. But enough depth to give me a reason to come back to the server the next day.