Blender Subdivision Modifier Global Increase/ Decrease

Problem: Viewport Performance can be slowed down by a large number of polygons that were created with a Subdivision Surface Modifier. And going through and selecting object individually and turning down their level can take quite some time. And selecting all object and hitting Ctrl+# can add reduce the modifiers levels but at it to objects that should be smooth.

Solution:
Have a Global Subdivision Surface Modifier that increase the level on all object that have a Subdivision Surface Modifier applied by either going up a step or down a step. The way this should work is by have these proposed keyboard shortcuts Ctrl+Shift+NUM+ to increase the level or Ctrl+Shift+NUM- decrease the level. This should be so that if there are object currently selected that they are the only ones affected or if nothing is selected than it should increase/decrease on every object with the modifier.

Thank You

Select via outliner, much faster.
Blender subd modifier and multires modifier, should be re written from scratch, making one only modifier with a few more functionalities. Like, “rebuild subdivisions” (an excellent tool under zbrush)
Should be re written for a more serious reason.
See how much RAM they consume. (2x or 4x of the expected ram)
I was thinking to start a thread on this development. But, I’m not a developer, unfortunately (or fortunately LOL)

If you want to limit maximum subsurf level for all objects you have the Simplify option in the Scene settings

Also you may see better 3d performance if the subdivision surface modifier is not at the bottom of the modifier stack. You can always add something like the simple deform modifier below it with a factor set to zero so it has no effect on your object.