> intercepts the main loop
This is optional, per transient menu (prefix) and the commands within it.
A common technique, used by magit and others, is to have entry point
commands in the regular keymap so that many commands can be started without
traversing several menus.  If you want normal un-shadowed bindings active
at the same time, the prefix has a slot called `transient-non-suffix' that
is similar to the `:suppress' option in keymaps or setting a `t'
`undefined' binding in a keymap.  However the results of mixing self-insert
and modal or modal and another modal are generally bad.

The biggest drawbacks of transient are well known in Github issues:
- Which-key discovery of Transient keymaps
- Transient binding generation based on keymaps
- Normalizing how to obtain arguments when being called independently as an
interactive command versus being called as a Transient suffix

In the short term, to punch the first two problems in the face, override
the `:setup-children' method.  If you know what keymap you are borrowing
bindings from, you can synchronize it at display time.

Regarding the normalization with interactive, if you are not using
transient infixes and instead lean on the :info class and dynamic
:descriptions, you can display state and store it using normal buffer-local
and defvar techniques, providing visual feedback for what might be hidden
states after the user gets more familiar.  The commands work with or
without a prefix currently active.  In this usage model, you only use
Transient for its flow control, display, and layout.  I find the infix
system to be somewhat of a distraction if you are not actually building a
CLI wrapper, but you can definitely make suffixes and descriptions "smart"
by reading a scope from the prefix and making custom infixes that also
obtain more state when displayed.  A custom infix for storing org elements
or objects could certainly be a thing.

I think deeper user customization is an area that is weak with transient,
but only because the user actually needs to have a vision for how they want
to build up stateful commands.  If you're just doing prefix maps, transient
and hydra are equivalent concepts.  Transient becomes differentiated when
you consider commands that build up state for other commands.  Executing
slightly modified command sentences in rapid succession is not something
the user customizes casually.  Complex commands only make sense when the
context they depend on is populated, which naturally decides the menu flow.

> I am wondering if we can work out some universal API to plug the
> described action->menu->selection model into the UI that user prefers.
>
> Tentatively, I am thinking about the following:
>
> For a given Emacs "prefix" command (e.g. org-open-at-point), we define a
> set of customizations:
>
> 1. List of possible actions: ((name1 . action1 props) (name2 . action2
...) ...)
>    PROPS is a plist defining extra properties like key-binding, display
>    string, maybe something else to be used in the future.
> 2. Menu interface to use (transient, context-menu, embark, which-key)
> 3. Layout settings for the specific interfaces. For example, transient
>    layout definition.

Well, I'm sure you know that transient has more decisions encoded in the
layout than the other options.  If the data going in is a least common
denominator, you need supplementary data elsewhere to achieve a good result.

What I fear is a system like org-speed-keys which relies on an override of
`org-self-insert' and is yet another orthogonal system.  I much prefer the
Lispy style of integration, which uses a keymap.  Using keymaps, even if
they are not active, to generate transient key bindings via :setup-children
is the best way to have certain integration with other Emacs tools.

How people can collaborate with me on general questions of design is to
open issues on the Transient Showcase.  Either I can point to an existing
example or make a new one.  I've been giving some thought to how to
demonstrate an idea more generally of composing multiple commands and
manipulating the composition to dispatch complex commands in rapid
succession with minor differences.  I personally have my own org speed keys
solution that I've been developing for yet another more complex package I
call Afterburner.  These projects can become stuck in design hell when I
don't have the prodding from other problem analysis, so please, bother me.

https://github.com/positron-solutions/transient-showcase