>>> Would it not be possible to write LaTeX with conditional compilation,
like when you write C++ programs, so that the same source code can compile
on several different kernels (e-TeX, TeX, etc)?
The question is, who will do the work? Volunteer work is a limited resource,
even in the TeX world which has many examples of very good software
provided through volunteer work. And maybe, there are other volunteer tasks
which have a higher priority.