Dan Hesse said WiMax will be a lesser used tech than LTE, but they went with that so they could have a product ready to go before other companies. They may even support LTE in the future. Sometimes being first can be a good thing, assuming a proper product launch. Last I checked, T-Mobile USA was in talks with Clear, to possibly use their network for 4G. T-Mo publicly stated this (
http://paidcontent.org/article/419-t...ith-clearwire/).
But, whether or not you can use the Evo in a non-US WiMax area will depend on if the frequencies are compatible. If WiMax in Mother Russia uses a frequency range outside of the Evo's capabilities, you won't be able to roam on it. Or, if Sprint doesn't have a roaming agreement with the WiMax networks in another country, it won't work either.