Bad, Adobe, Bad! I still want mirror layers! (layer instances)

Question

I NEED to apply the SAME layer with different blending modes TOO OFTEN, and I keep doing the filesize TO GROW!
Not to mention that I still have to patch all its copies when I need to modify it / them.
I though creating a copy of a smart object, yes, I can edit one and all of them will change, but:
It's difficult to tell whether you are working on the instance of the smart object you want or a copy of it.
You have to go to ANOTHER window to edit it (because of the resolution could be different). Off line editing IS NOT Photoshop-ish
Once you save your file with many copies of the same smart objects THE FILE SIZE GOES CRAZILY UP!!, ( I edit it and all of them change!, so I can tell all of them are copies of the same ) so those smart objects are NOT THAT SMART!
So, you could fix it AT LEAST with a little checkbox stating "disregard filters below this one" or "use unmodified layer for this filter".
That way, you can add MORE filters to the same layer, but OFF LINE, as if you had created a new layer on top.
Then, I could create a bizarre trick like "GAUSIAN BLUR = 0" OR "CURVES 0, 255" to get NOTHING ELSE but the original layer to add a new blending mode to.
To prevent all that work-around, you could just create LAYER INSTANCES! (mirror layer, in-line-edit-able smart-er objects, or so)
THANKS!

Answer 1

Do I have to go further to explain how much the file-growing thing makes no sense?
I hope Mr.Cox explanation was satisfactory.
You have to go to ANOTHER window to edit it (because of the resolution could be different). Off line editing IS NOT Photoshop-ish
I myself disagree, but some people seems to be of the same opinion and have in at least one instance caused me additional work by rather doing touch-up in two sizes for two different products, in both of which the image was differently clipped, so that when I needed a less clipped version in full resolution I had to recreate their edits.
But not only can the resolution of containing document and SO vary, they may even be of different color modes and depth.
So I suspect to edit Smart Objects in their »surroundings« Photoshop would have to temporarily totally reset tools, surreptitiously change the mode, counter-calculate the Transformation for the SO (and the containing document) and redraw Filter-applications on the fly while the edit goes on; which would seem (possibly prohibitively) complicated to program and a performance-chomper especially when having to redraw multiple instances.
Moreover if one were to paint on a layer of the Smart Object (while staying »within« the containing document) and exceed the SO’s original format a previously applied Transform or Warp would have to change.
But maybe Mr.Cox could tell if he considers it achievable at all.