Hi guys
I started along time ago programing with Visual Basic (mostly self-teaching). Then I learned C (formal course). The change between both languages at a "basic" level is just a matter of knowing the syntax. Then, moving forward C++ is pretty much straightforward. I repeat, at a basic level. So, I would say that modifying current code, and compiling new simple modules is an quite easy task.
I agree that PJSR would be an even easier approach. But it has limitations. As a matter of personal tastes, I think that C++ code is more elegant, nicer, than JS, but that's only my own p.o.v.
Also, I believe (I might be wrong) that it gives more control over what's happening behind curtains.
Anyway, I think (or believe) that in the med-term both ways of expanding PI would merge into some state where for a final user it would be hard to find if a process has been implemented as a c++ module or an "advanced" script. So, I wouldn't care too much about the path to follow. Also, you may go both-ways
JS is a great choice to test new, rough code, which would later be implemented in c++.
PS: Sorry for being away from the forum. The academic life has much higher priorities this month.