After playing Falcon 4.0, I'd really *love* to buy DCS but I just can't think of playing a sim without a dynamic campaign...it's just essential for me. DCS looks beautiful and from what i have heard, its flight model and mechanics are awesome. Now all it needs for me to purchase is the dynamic campaign.
like many have already said, with a persistent DC you feel as though the game is ALIVE, your actions have lasting consequences...so you plan not just "tactics" for a single mission but instead you think strategically and long-term. differnt actions result in complete randomization of the entire "game world" too, which adds replayability value. a DC would really add an immersive/addictive level of depth and richness to a game such as DCS...proof of this is clear from comparisons i have read by people who own both DCS and Falcon 4.
i will continue to lurk in these forums from time-to-time and hope for an official annuncement confirming plans to develop this aspect. current DCS fans want it, potential fans want it, YOU want it and the world wants it. you know it makes sense ED - DCS deserves this! ;)