Art,
I did upgrade to a top of the line Netgear wireless N router recently from a secod or third generation Linksys that I had been running for years. I found this has helped with throughput to my Rokus, which are only wireless G, despite technically the same maximum wireless bandwidth, in that the range appears to be greater and I believe the processors and software used are faster and more efficient.
We tend to forget sometimes that devices like routers are just specialized computers with specialized processing, software etc. This kind of processing generally gets better and faster over time, and not all modern routers are created equal. A faster more efficient router still helps even if the pipeline from router to wireless devices still has essentially the same capacity (wireless G protocol) as before.