Decent power, enough grunt to be a nas and dual lan ports for routing. Or get a decentish router with wifi and snap up a raspberry pi to do your nas work.
There was a time that picking up an all in one device to do your home network was a no brainer.
However with the advance of tech and easy of use of things like the Pi. You might just find that seperate networking components are easier. Getting a router like the R4S, then maybe a wifi unit like a ubiquiti ac-lite (cos it will be miles better than most ISP router wifis, throw in a cheap 8 port switch or even an ex-corperate rackmount switch if u have lots of devices to wire up and you end up with a much better solution. However its how much of a solution u want vs cash you want to spend.