Happy April the First!
And the Pentax weighs 405g, measures 73mm x 76mm and takes 62mm filters.I am not a Pentax fanboy. Indeed the fact that the XT1 is on my short list to replace the K3 confirms that. But this new Fuji is a bigger lens than the Pentax with no larger aperture at either end of the zoom range. The Fuji weighs 490g, measures 76mm x 98mm and takes 67mm filters so it is definitely bigger.
"The Pentax 18-135WR has poor optical quality".Really? You have used one? My copy at least has perfectly acceptable optical quality. Is it as good as a wide aperture prime lens? No. If the Fuji version has even better optical quality than the Pentax then that will be excellent.
I have the Pentax 18-135 WR zoom on my K3. It is only a 62mm filter size but has the same f3.5 - f5.6 aperture range as this. I need to seem them side by side but I suspect the Pentax lens is smaller. I am thinking of going totally mirrorless for all my photography but if the Fuji lenses are bigger than the Pentax ones then I need to look at the Olympus EM1 or just stick with the weight and bulk of the K3. These are only tools when all is said and done! I just want to carry less weight around, being in my 60s and a bit lazy!
Lights: Wide end isn't a portrait focal length so 3.5 doesn't give background blur:who cares. Wide end is for extended DOF.Macro is .72 better than some with that label(macro) and maybe handy if only one lens with? Again all faster apertures do for macro is make the DOF so thin that it's unusable.Yeah it could be faster at the long end...and is bumping against diffraction.The power zoom I could live without, but might be good for video shooters. Oly is calling it a "standard lens" and it is weather sealed. So looks like a weather sealed M43 body is coming along and this will be a kit lens for it quite possibly.
Actually the Pentax K5 is truly weather sealed and is cheaper than the D7000. I am not sure that the latter is weather sealed in any case.