Hmm... Looks pretty similar in demensions at least to the existing design, just adding Tamron's zoom lock...

The only thing with the old KM version is zoom creep when walking around. The lens hood fits nicely on the lens reversed, not taking up much room. I use a thick rubber band and fits nicely over this, keeping the lens from zooming out when walking around or taking the lens in and out of my bag... No biggie...

And yes, it's very sharp at f4+, and still quite usable all the way open.. I'm sure you'll be quite pleased with this lens...

The flower type hood seems okay for landscape mode shooting.. Haven't had any lens flare issues that I've noticed... When I'm carrying multiple lenses with me, this is my primary walk-about lens...