Haven't fully read the topic, but you can make suggestion to [email protected]
Personally I did two proposal last months, better size control on param panel and more informatios needs in "params" variables for updateFn (you can have a look into params by using datadumper, there are some environement variables, I suggest they put more thing like the edge info around the cursor)
Lol, make me recall the evolution of ETCS/ERTMS!
Local functions: a number of capabilities in the Lua scripts of TpF are declared as local. This means that you must copy for small changes often hundreds lines of code and thus exacerbated the compatibility issue.
This is performance issue of Lua, local is much faster than global.
That's why I made a lib of my own: I have control over everything. Unfortunately this made me each update is for all mods..
In fact the thing could be done in this way:
You have seen in mod.lua you have hooks, but the effect are global.
I don't know if for UG it's possible to make is effect local, if it's possible, let them add a hook of function! 
I think your proposal means to add hooks in framework functions so a mod overrides callbacks instead of the function(well, callbacks are themselves functions), the problem for them is where to place them...and so they need to make a standard process for construct everything... The problem is, the capacity of vanilla script is very limited..
And the de-facto standard for modder is Tom's script.