Weight painting with preview visual feedback

Proposal:

In Weight painting mode, when holding Ctrl+shift and hovering over an area of the mesh you would see a preview of a weight of 1 (weight value maybe could be controlled by mouse scroll) and see how that would impacts the mesh deformation.

When releasing Ctrl+shift nothing is actually painted.

Why?

In a complex rig it's sometimes difficult to know how a specific Vertex Group is impacting the deformation of a mesh in different poses.

By having this feedback you would be able to easily see how that Group is impacting the deformation. This would avoid painting over the wrong Vertex Group and having to undo when it didn't have the expected result.