P: Increase the strength of the blur tool.

BTW: I've always suspected that the "Lens Blur" filter's feature to use a channel as a blur map, is precisely the reason why it can't be used as a smart filter. That's a whole new level of computation that no other filter process has to do, and would probably be difficult to code without causing crashes. Makes me really sad, because I'd LOVE to have a compound blur as a smart filter. I often just throw up my hands and do this kind of stuff in After Effects, which has a lot better handling of compound blurs.
Sorry for the off-topic.

It's not a filter, it's a tool. The blur filters work just fine. It's the blur TOOL that we all have issues with, and there's really nothing to figure out, it just has no settings. The sad part is that other than the incredibly powerful but broken Lens Blur filter (it's the only blur that can not be used as a smart filter), the blur tool is the only way of creating a compound blur, that is, make part of an image more or less blurry than another. And as Lily Skove mentioned, that makes it incredibly useful on layer masks. I believe it's a huge oversight on Adobe's part.

Surely a weak-to-strong slider wouldn’t be too hard for users to grasp.

Even though I don't have a need to blur that you do, I would like to see if I can help. I know a great deal about these kinds of filters so maybe I can get a definitive answer to what you want and then figure how to do it.
RONC

I frequently need t to create layer masks around my products photographed on white - one of the most common photography scenarios.  The problem is that when I convert a pen tool path into a mask, I need to be able to selectively choose which areas have a blurred edge mask, and which areas should have a sharp line in the selection.  When you take pictures of small products its often nearly impossible to get everything in focus at any aperture.    So this is extremely common for photographing small products.  I want to use the blur tool to soften parts of the mask, but the blur tool is so weak its almost completely ineffective.  I think this is because I'm always working at 5 and 6k resolutions.  This also makes the blur tool useless for many photos and I have to use a blur filter instead.  But a blur filter is not helpful when you are needing to selectively blur parts of the mask itself.  So mask manipulation would be WAY more powerful if you would make the blur tool more powerful.  Like up to 100x more powerful.  I'm not sure if the blur tool is so weak because its a legacy tool from times when we only had a fraction of the resolution in our photos to work with.  Whatever the reason, there are a lot of people asking for this, and it would save me hours of workarounds to have this simple obvious tool enhancement.  Thank you!

One thing I noticed is that even if it's a very mundane change, developers are really hesitant to change the operation of existing features. This makes a certain amount of sense, as many users go "BUT WAIT, IT WORKED DIFFERENTLY THE LAST TIME I DID THIS!" Probably the best solution would be to create a toggle that says "Blur More" (which fits with their terminology), that would increase the blur by a power of x4-10 or something, and have it off by default.

It is such a simple thing for Adobe to modify the capacity of the blur tool. I don’t get the resistance.

I think the problem is that in the time since the blur tool was introduced (heck, to my knowledge it's always been there, at least since the mid-90s), resolutions for most tasks have skyrocketed. What once probably made a definite difference to our low-resolution graphics, means nothing to today's 5k+ images.
And the workarounds aren't all that perfect either. The nice thing about the blur tool is that it can be gradiated, creating various degrees of blur. Where-as, copying the layer, blurring it, and masking out parts may get the right results in some cases, but it doesn't allow for subtle gradations of blur between the regions. This comes back to my bigger issue that Photoshop is really behind it "compound blurs" compared to After Effects. The only compound blur we have is the Lens Blur, the only effect not able to be dynamically inserted into a smart object, that looks to a particular channel as a blur map. Lens blurs are nice but they are often overkill and processor intensive for day-to-day needs, and their CPU intensiveness is what probably prevents them for being added as smart effects. If we could just have a regular old compound gaussian blur, that would be money.

Hmm, yeah, that is still too weak for color blending unfortunately. 🙂

You use a high brush spacing, which is why the high scattering count doesn't cause lag. You could also disable scattering and decrease the spacing to 2-3% to achieve a similar blur, while also avoiding the unpredictability in edge control that scattering brings with it.

Setting the size control to Pen Pressure with a minimum diameter of 100% is the same as setting it to Off by the way, so you might as well just untick Shape Dynamics. 🙂 Transfer > Strength Control set to minimum 100% also equals unticking Transfer altogether in this case.

Thanks for taking the time to share it!