Some problems: the colours are not that great, and also not colourblind-safe. And most grating of all: why are the tics light gray and not black! It's very hard to read.

Xkcd style perhaps? https://github.com/rfonseca/xkcd-gnuplot

Just curious but why go for gnuplot (and awk) rather than python or R? At some point you run up to some limit where you want a bit more capability. I don't know that the learning curve is that much less for awk + gnuplot?

Gnuplot (and awk) have several advantages. It’s faster, especially for large datasets; it’s language-independent and can be used through pipes with any language, so the plotting solution you develop can go with you as you change your simulation language; it’s designed to be automated, plot over the network, etc.