Because the speed of the ISP matters, it's rarely an issue caused by the router. Also, for each Hulu, Youtube that means that it adds up fast. No router will add more bandwidth to what the ISP delivers.
That said, I do like the newer routers with dual core processors. I picked that since I wanted to use the NAS and found my prior router seemed to slow as the HDTV DLNA'd. Now it's better.
As to range, over the last dozen routers, range has been nearly the same. No router over the years has say doubled the range of the prior model.
Opinion: It's not the router but your internet connection speed.
Opinion: Which wireless router: DLink AC3200, Asus RT-AC3200 or Asus AC2400 RT-AC87U for the home, that would best run a combination of ooVoo, Minecraft, Hulu Plus, FaceTime, PC, Instagram, YouTube simultaneously on separate devices with the minimum amount of buffering and adequate range. Optimum cable internet speed 50/25. Recommendation please. Thanks!