IMO it's a step backwards for anyone in the enterprise. I think it's clearly aimed at the home user, doesn't fully replace SL Server, and leaves a gap for those who actually need to dig into Apache, VPN, etc.
For some services you have to use the kid-gloved "Server.app", for other services (like Open Directory), you have to use "Server Admin.app", it should be one or the other. Server Admin has never been great, it's had its fair share of bugs in the past, but there's never been a forced split like this. And unfortunately because of how Server Admin works you can't simply use the command line for all things. Some services have been outright removed from Server Admin, like iCal, Address Book, and VPN, and moved to Server.app, only then to be over-simplified.
With the various posts & reports of odd bugs with 10.7.0 "client", I'm not upgrading my Mac until at least 10.7.1, and certainly not my Xserve until then or perhaps not at all.