I preordered way back in first week of January from B&H and got in on the first wave.
As to the softness, don't judge the lens, I accidentally shot most of this series at F18 and auto ISO. That would have been fine on my 6d but tge 70d doesn't do real well in that 3200 iso range. The softness was sort of intentional in a couple of shots to make the water appear surreal and was a byproduct of noise reduction primarily.
If you want evidence of the sharpness this lens is capable of go to my Flickr account and look through the Tamron 150-600 set. Much better represented there.
I looked at your flickr gallery and there I see a lot of great and sharp examples taken with that lens. The leave pictures don't do any justice to the lens..lookes like a killer lens!
For myself I'm deciding between the Sigma 150-500 or the Tamron...hmmm...doesn't make it easy...