I would say it says more about the perception of what this will do versus "need" per se.
Many users myself included have never seen WiMax in action. I have asked the few users who are in possession of a device for comments about it. Most of us have seen 3G and what its capable of on smartphones and tethering to our tablets so we have a better frame of reference when HSPA in Maemo 5 is referenced.

Personally, I think that with a more robust network rollout a Wimax equipped tablet could give regular cellular networks a good run for their money. I believe you can do SMS over IP and of course we know about free ways of using VOIP. So the fact that you can get mobile talk/text/web and home talk/text/web for $50 flat rate is astounding and warrants more attention.