One thing Apple routers had was the ability to set themselves up as a Bonjour proxy, so for example your Mac could advertise its iTunes library sharing, but go to sleep. The router would repoint the address to itself, and if you tried to access that library from another device, the router would send a wakeup to the Mac, then repoint Bonjour back at it.
Also, while the rest of the world uses uPNP, Apple routers use NAT-PMP.
Are these technologies just dead now?
And in response to the comments above about more availability for network drives to be used as remote Time Machine backups, instead of requiring a Time Capsule, will Apple decide to kill off remote backups entirely because the experience is no longer guaranteed or even consistent with third-party devices?