What features from a typical wireless router is Airport Extreme missing?

Are there any features that Airport Extreme is missing that typical routers always have?

For example virtual servers, dmz?

Have you seen the Technical Specifications for AirPort Extreme, that should cover most of the questions. There are no virtual servers and no DMZ, but IPv6, Port Mapping, Shared Disk/Over-the-Air-Time-Machine-Backup, Shared Printers, DHCP and NAT, some features are Mac-only, of course. Wireless 802.11n with various transmit power options. That's about it. As I said, no toy, but it works 100% reliable, even for techies.

The main limitation is you get one VLAN and it's called the guest network. You don't get fancy VLAN, QOS traffic shaping or routing treatment of advanced routers like the cisco corporate line, but it's very full featured for a consumer or small business router.