Wikipedia states:
"Wireless Multimedia Extensions (WME), also known as Wi-Fi Multimedia (WMM), is a Wi-Fi Alliance interoperability certification, based on the IEEE 802.11e standard. It provides basic Quality of service (QoS) features to IEEE 802.11 networks. WMM prioritizes traffic according to four Access Categories (AC): voice (AC_VO), video (AC_VI), best effort (AC_BE), and background (AC_BK). However, it does not provide guaranteed throughput. It is suitable for well-defined applications that require QoS, such as Voice over IP (VoIP) on Wi-Fi phones (VoWLAN).
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IEEE 802.11e-2005 or 802.11e is an approved amendment to the IEEE 802.11 standard that defines a set of quality of service (QoS) enhancements for wireless LAN applications through modifications to the media access control (MAC) layer.The standard is considered of critical importance for delay-sensitive applications, such as Voice over Wireless LAN and streaming multimedia."
So if the router is IEEE 802.11e compliant and implement correctly the WMM, then he should see an improvement (but we still did not account any interference he might have)...
About netflix... i do not have/use it, so i have to take your word for it....for now. Maybe someone will play with wireshark to see exactly how they transfer data...