I'm just a user here who posts a lot (probably should change that as well) and just got a mod badge to being able to do more on the forums - in no capacity am I speaking for what the devs want or do.
I also have no illusions about what my ramblings cause in the end - most of it will run down in history as 'blah bla bla ..'
Really need to add a disclaimer to my posts it seems.
You can't fix issues that sit OUTSIDE of your sphere of influence caused by a minority who doesn't apply bugfixes to the software they are using.
And there is no need to do any coding to convert arcs into circles every time.
Just change the libs, add a note to the KLC and set the standard export to 4.5.
Done - IMHO.
If you were fixing it at all you wouldn't stop there, go for line segments I say.
Go straight for the root of the problem.
I don't wonder about that one really, but I'm pretty sure it's not because of me or my suggestions.
99.9% of the people who want to or do use KiCAD don't look for another past-time-coding-project, they simply want to get from circuitry to pcb assembly as comfortable as possible and simply have no time or interest in dealing with the code of the tool.
The 0.1% that does have the ability and desire to change things will probably do fine and join the KiCAD IRC channel and the dev mailing list and work from there - probably never to be seen on KiCAD.info again.
PS: I haven't looked at the source once since I'm using KiCAD as I have enough other stuff to deal with already.