You can not take a technology in mid-build and claim it is so all over.
Leaves and trees should not effect your signal a whole amount. Wimax automatically adjust strength for degradation.
So the more scrambled your signal the more power is used.
But this really does depend on the build out. If you are at a BASE station or a REPEATER station.
It also depends on the amount of energy being used and your chip in your receiver.
I have done extensive test on wimax. I have found that for the most part, a 6-10mbps promised speed can be achieve to the end of the signal strength.
Yes buildings and mountains can deflect the signal. But the cost of filling these holes will be less then lte deployment.
I am not doubting your statments but would blame it on a weak receiving chip, clearwire's old chip set, and the use of a repeater instead of a base
station.
Like any coverage, given time, the holes will be filled.
Lte will be worst given the high cost of building out the next work and it can not boost signal strength to over come degradation.