MichelRE: I think it would've helped if you'd mentioned the circumstances of what you were doing. Were you
hired to do this notation? If so, I'd good-naturedly offer the client my advice, then be prepared to accommodate them if they stuck to their guns.
If I were preparing music for a group I played with, I'd do the same—on
their parts, the ones they'd be reading.
As far as your other questions go—and as others here have pointed out—people have had all sorts of ideas about "improving" notation. Taking a big view, I suppose that if they hadn't, we'd all still be reading things like this:
(Or maybe not even that good!)
I'm sure you've seen forms of symbolic avant garde notation. What you describe falls far short of that. However, I think we must acknowledge that "notation" occupies a pretty wide spectrum—and that what may fall outside of our own preferred practice may just be someone else's idea of how music could be represented and interpreted.
You won't catch me using such things as alternative glissando lines or "micro-dynamics" in my own music. But if people want
their music prepared a certain way, I don't feel it's any more appropriate for me to say how that should be done, than it'd be for me to tell an artist what paint colours to use. Cheers!