Gaming requirements are subjective. There is no such thing as a "Gaming Router", only a router that fits the needs for a particular category of games. First we need to identify the protocol mainly used for communication such as udp (realtime) or tcp (mmorpg). TCP is not a big deal but udp is because although udp is punt and hope protocol we don't want excessive drops. Small packets will not cost much bandwidth but do require processing power and low latency. A realtime vs mmorpg game makes a huge difference in overall needs to fine tune things. I would recommend a router with at least 1gig cpu and 256+ of ram and wifi duties on a seperate access point. QOS helps a bunch but still hurts when dropping udp packets. Consider the average size of a gaming packet is between 150-250bytes. an example:
200bytes-per-sec *8(bytes2bits)x60packets-per-second)/10mbits=0.0096 miliseconds.
That's critical when every split second decision counts.