These factors allow a typist to deliver information more quickly than constantly having to use the mouse, menu and awkward ctrl key combinations while reducing typist memory overload thus making the typist more effective and thus higher paid.
Excellent, this will allow you to pay a developer to code your chosen user interface paradigm.
When software is developed and maintained by unpiad people in their own time they will work on what they are personally interested in. The more complex the software is, the more time people must spend in unpaid uninteresting maintenance activities and the less time they have to work on what interested them in the first place. Snippets is a simple function to insert small code templates into the buffer, it is not a complete alternative user interface paradigm. Having several user interface paradigms adds to the complexity of Geany core software.
It may be possible to provide such a UI in a plugin, similar to the alternative UI the commander plugin provides.
If someone makes and maintains a plugin to implement the modified UI paradigm thats fine, it does not unnecessarily impact on the core complexity and maintainability of Geany.
The alternative is to make complex set of judgments that some of these combinations are valid and some are not.
Indeed, and that de-facto judgement is what has been made with the functionality that has been provided by contributions of code to Geany core, it uses the standard GUI paradigm that mixes mouse/menu and shortcut keys and which mostly suits the programs contributors.
We should all do our best to reduce the decline in productivity
The purpose of Geany is not to address any putative decline in productivity, it is to develop a "simple fast lightweight" IDE for the purposes of the contributors.
That it is useful to others is good, the contributors are happy that it is useful to them, but contributors gain little from extra users, in fact there is a support cost to bear and the contributors have no obligation to provide any support for enhanced levels of user productivity or any other specific feature or functionality that they themselves do not wish to contribute.
As I said above, if you want additional or different functionality so you get paid more, then you should invest to get that return by having a developer make the functionality in a plugin for you.
You may then keep the plugin as your personal competitive advantage or you may wish to release that plugin to the community in return for the many tens of man years of work you are getting for free in the base software.