Spot Removal tool should be an extension of the Adjustment Brush

Question

I am glad that LR is taking steps in the right direction to improve the Spot Removal tool with the new Healing Brush feature. However, I agree with others that the interface needs improvement. Though I am probably not the first, I feel I have the solution:
Integrate the Spot Removal tool into the Ajustment Brush tool. Here's why.
I think an improved interface for the Spot Removal brush tool (Q) already mostly exists in the in the form of the Adjustment Brush (K), and indeed the two tools should share the best of their respective features and controls. The current Adjustment Brush has most of the features we are looking for in the Healing Brush:
Pre-brushing Size of brush (already implemented in the Spot Removal tool)
Pre-brushing Feathering control
Pre-brushing Flow/Density control (already implemented in the Spot Removal tool as Opacity)
Partial erasure of selected brush stroke masks, while maintaining the above brush controls (by holding the ALT key in Windows, aided by making the Mask Overlay visible (O))
Pre- and Post-brushing adjustments of each Spot Removal brushstroke for White Balance, Tone (Exposure, Contrast, Saturation, etc), Sharpness, etc.
Adding the above features would be an incredibly useful approach to the Spot Healing tool, and would be a natural extension of the interface we already are familiar with. Both the Adjustment Brush and Spot Removal tools could be further improved by these additional features:
Post-brushing Size of circular brush (already implemented in the classic Spot Removal tool)
Post-brushing Size of painted brushstroke (supposedly already newly implemented in the LR5 Beta Spot Removal tool, though I haven't been able to get it to work on mine)
Post-brushing Feathering control
Post-brushing repositiong of painted brushstroke (already implemented in the classic Spot Removal tool)
In summary, the Spot Removal tool should really be an extension of the Adjustment Brush. They should live in the same control panel (with a Clone or Heal ON/OFF toggle switch). The Adjustment Brush could benefit a bit from the addition of a couple of the existing post-brushing features of the Spot Removal tool.
The two tools are really one tool, they just don't know it yet. Let's introduce them to itself.

Answer 1

A few weeks ago, I posted the silly graphic above. It is a Venn diagram of my interpretation of Lightroom 5 Beta's three main local adjustment tools' strengths, weaknessess, and overlapping powers. Each tool - the Adjustment Brush, the Spot Repair & Advanced Healing Brush, and the Graduated & Radial Filter - has one or more discreete powers or traits. The three tools each overlap a neighboring tool in an important aspect (e.g. the Adjustment Brush and the Advanced Healing Brush can each be used to paint any freehand shape to be adjusted). By default, the descreet "Super Power" of one tool is a "Super Weakness" of each of the other two, which lacks that power (e.g. the user can make additions or partial erasures to any mask overlay with the Adjustment Brush, but neither the Advanced Healing Brush nor The Radial Filter has this power).
In the very center of the diagram is the overlap of all three of the local adjustment tools. In this triple-overlapped zone, there is currently no existing tool. I theorize that there could be a special sort of new local adjustment tool, which combines all of the powers (and none of the weaknesses) of the individual tools of which it is composed. Inspired by the notion of cartoon supeheroes teaming up to combine their powers, I gave it the tongue-in-cheek name "Super Friends Awesomesauce Brush". However, my vision for such a tool is completely serious. Basically, I envision it as an "Advanced Adjustment Brush"
For example: 
Paint a shape on the image with a feathered brush. (A transparent colored mask overlay guides the user in the same way that the traditional Adjustment Brush does, as lollololli correctly suggests above as an easier way to paint a selection.)
Pick up that brushstroke with the mosue and place it in another part of the image.
Enlarge or reduce the overall size of the brushstroke with the Size slider.
Increase or decrease the overall feathering of that brushstroke's edges with the Feather slider.
Erase with the freehand erasure brush the portions of the mask that you don't wish to interact with the image.
Convert that brushstroke into a healing repair.
Resize that repair shape larger or smaller, and/or change its aspect and rotation as needed. (Transformations to the shape of the target brushstroke, not necessarily transformations of the shape of the healed or cloned sample pixels)
Increase or decrease the exposure or color temperature of the repair.
Or,
Create a new Radial Filter on the image.
Adjust the exposure, white balance, Gaussian blur, etc. of the filter.
Subtract from that Radial Filter by erasing with a second erasing Radial Filter at the same pin-level
Add back to the Radial Filter with a freehand feathered brush as desired
Or,
Maximise the brush size and minimize the feather setting and paint a solid mask overlay over the entire image.
Convert the mask overlay to a Clone repair - you have now created a second duplicate layer of the entire image on top of the original (BTW you can already do this step with the Advanced Healing Brush set to Clone and size 100 in LR5 Beta).
Subtract from that clone repair with a Radial Filter erasure to create a "hole" that shows the base image underneath.
Make independent exposure, white balance, and sharpening adjustments for both the base image (seen through the Radial Filter subtraction "hole") as well as the cloned top layer.
Reposition and resize the Radial Filter erasure as needed.
Add to and/or erase from either the Radial Filter erasure or the cloned top layer with radial filter shapes or freehand brushstrokes as desired.
I see this proposed Advanced Adjustment Brush as a very powerful localized adjustment tool. Although It really isn't a new tool at all, because it is almost completely based on the existing local adjustment tools. Additional enhancements (more geometric shapes such as polygons) could take its flexibility even further.