Actually I like win2k8 so far in my virtual machine, especially the server core abilities and the virtualization (still undecided on powershell in general). I just don't see any reason for a small shop to care about upgrading an existing working production Exch2k7 server's OS. If you don't have the budget or the hardware to support the move, just keep using what's already working. Rule number 1, if it ain't broke don't fix it.
As for the added complexity, hardware requirements/specifications, and scalability of the newest range of MS server products, they have to do something to get more exposure in the "super gigantor global bigger-than-most-2nd-world-countries enterprise" market, and building these types of products should give them more good answers for their pre-sales engineers when on a conference call with a sr. admin or a technically inclined "C" who knows what he really needs for his environment.
Plus they can get away with it now since SBS2003 is an outstanding solution for Small Shops, and I'm sure by 2009 their "SBS2008" product will be in the same level of excellence.
The only market stuck between a rock and a hard place seems to be those 75-200 user companies who struggle with the new hardware requirements for the new products (plus the obvious licensing costs), but I'm of the opinion that they should keep using the old products on the old hardware until hardware pricing drops a bit, and pick their MS products more carefully based on business needs instead of the mindless "we're a MS shop" approach to all things IT.