One hotkey=long list=listitis
Doable not workable
Sorting out via conflict pallet
Again doable not workable in simplicity of a light switch kinda way.
If you haven't read or watched David Pogue's Ted Talk "Simplicity Sells" "David Pogue: Simplicity sells | TED Talk"
Here's a piece:
"Now, I'm not saying that Apple is the only company who has embraced the cult of simplicity. Palm is also, especially in the old days, wonderful about this. I actually got to speak to Palm when they were flying high in the '90s, and after the talk, I met one of the employees. He says, "Nice talk." And I said, "Thank you. What do you do here?" He said, "I'm a tap counter." I'm like, "You're a what?" He goes, "Well Jeff Hawkins, the CEO, says, 'If any task on the Palm Pilot takes more than three taps of the stylus, it's too long, and it has to be redesigned.' So I'm the tap counter."
Taps are clicks or taps on a trackpad and function as an action the user must take to get something to happen. Moving from the keyboard to the trackpad/mouse counts as at least one action and examined more closely lots of smaller actions. Locating the cursor is an action, moving/tracking the cursor around the screen is an action. Clicking on a conflict pallet is certainty an action then clicking down thru a series of conflict pallets (scrolling over a list that activates by hovering over so you can just glide rather than click down thur is smoother) is a series of actions/decisions with each conflict pallet functioning as a list to read and respond to. Very doable and from within the looking of staying within the current paradigm/available feature set is a fine way to go and doesn't open the envelope/break any chains.
Quadro
Like/challenge: Takes over the whole iPad/iPhone screen: would need to appear/disappear in a hurry as a form of elaborate pallet. Appearance/disappearance speed needs to be adjustable to suit viewer. Final brightness/transparency needs to be adjustable as well.
Like that with BTT it could be evoked with a swipe or tap on the trackpad.
Tapping on the trackpad note:
Another factor in all this (no eyerolling please) is what it takes to press a key on the keyboard. My fingertips are really sensitive and the sensation of typing is not in the pleasant realm for me which is in part why I dislike typing. The newest chiclet style magic keyboards that come with the newest iMacs are the best ever by a long shot and still nowhere near a pleasing as the very light taps and scrolling/panning that the magic trackpads provide.
Colors/shapes/icons intermingle to play a central role in easing cognitive load of locating desired action. Someone with a "artistic eye" (not me) could create a pleasing harmonious pallet of colors/shapes/icons that are a pleasure to see each time they show up. The current set as shown is simplistic and child's blocks kindergardenish hard and bright and fatiguing to see. This approach still incurs a creating and learning a new language/shorthand cost so must be worth the investment and compelling enough to draw the user in.
I assume you mean all the options in the dropdown menus within the "Available in all applications." etc. menus. Yes, I've seen them and haven't done the work of thinking thru how to use them in combinations beyond limiting pallets to showing up within a single app and "Shows a pallet for one action when:" to get it to show up for hotkey activation. How are you using these settings to get what to show up?
KM wiki says:
"Keyboard Maestro uses ICU Regular Expressions (aka RegEx or RegExp) which is very similar to PCRE (Perl Compatible Regular Expressions), and you can read their documentation by choosing ICU Regular Expression Reference from the Help menu in Keyboard Maestro."
Hmmm...
The ICU Regular Expression Reference page starts with:
"ICU's Regular Expressions package provides applications with the ability to apply regular expression matching to Unicode string data. The regular expression patterns and behavior are based on Perl's regular expressions. The C++ programming API for using ICU regular expressions is loosely based on the JDK 1.4 package java.util.regex, with some extensions to adapt it for use in a C++ environment. A plain C API is also provided."
This is above my paygrade 
and there is a significant price to pay to play within this powerful arena. It's a fine path that I'm not currently walking. It's a well developed language/sets of concepts to learn and practice. What do you make of it? Yes give me some small bite to chew on for awhile.
Please share your catch when you come back to the surface.
BIG "IF" here. I went down this rabbit hole and ended up with some very nice examples that were very patiently and very generous given to me:
Not sure how to reference another thread. Here is a copy/paste of the URL:
I played with and used the examples a bit but then they broke and I couldn't fix them and rather than spend the time to learn to fix them, which would have been worthwhile, I just abandoned them. Feels crummy to say, like I did something wrong (pass a tissue please ;))
Yes, as an outcome of good design the result must be welcoming. One useful meaning given to "Enrolling" has been to leave someone in action. One is enrolled into something when the exposure to it leaves you in action. So a welcoming entrance leaves you walking thru it not just standing at the threshold. A welcoming/enrolling pallet/action leaves you evoking and using it.
Your being enrolled in this conversation leaves you taking the actions to reply. Taking action is perhaps the most important outcome of providing space. Not just any old space or opening but a space you are compelled to and do actually enter and engage with.
Please tease some of this out. Say what you've seen. I think we are WAY pass discussing a topic and into a general conversation about design which I hope isn't breaking too many rules or countering the intentions of our hosts 
. The ice feels thin here...
Just me foolishly trying to manage the unmanageable.
(This in my not humble opinion–shoot me now–is the motherload) Yes and the next step is to ask why. "Every child is an artist. The problem is how to remain an artist once he grows up."—Picasso
One of the best expressions of this issue was in Ken Robinson's Ted talk "Do schools kill creativity?" Sir Ken Robinson: Do schools kill creativity? | TED Talk. Seems way off topic like a trip to the moon off but I couldn't agree more that imagination IS missing.
I think the biggest ingredient is just not having the guts to take the risks. Takes huge courage to step out of the crowd. To stick your neck out, to be vulnerable (meaning to be open to harm).
More immediately, the urgingly impatience that comes to grip us when we start to feel the need to do something, to accomplish something, to get something done (which often but not always is the case) that urgency that drives us past just "being with" something that won't "let it be" that almost impossible realm of being is where a conversation about design leads that drives the folks who can only tolerate the practical, crazy. Just on the other side of that final urgency is a spaciousness, a wide open sky of clear lightness and endless possibility/creativity. It takes something to get pass the strong feelings to move and take action rather then just be with and allow/remain in the experience, in the moment.
“Be patient toward all that is unsolved in your heart and try to love the questions themselves, like locked rooms and like books that are now written in a very foreign tongue. Do not now seek the answers, which cannot be given you because you would not be able to live them. And the point is, to live everything. Live the questions now. Perhaps you will then gradually, without noticing it, live along some distant day into the answer.”― Rainer Maria Rilke
Content for now...
Next is back to the immediate, get intro letters out, get more business, make money, make car payments and holiday gift happen, chop wood, carry water.
Thank you again for this enrolling space you've open. It's been a gift.