From using gnuplot of a few versions ago for tasks involving rather many plot generation, I felt that the gnuplot syntax and commands are rather unintutive and hard to remember, perhaps in some way aesthetically jarring. Also the interactive plots it generated was rather barebones.

Plotting from a pandas dataframe seems more convenient way than using gnuplot presently.

Yeah, I agree. Though actually I like plotting from Julia the best. You see software like gnuplot a lot: started its life just doing one thing and then slowly growing. The end result is an unholy mess of a system. All things eventually end of being Turing complete, so let's just eliminate the middle man and use a programming language.

Other examples of this are html/js, excel, vim, and bc.

A much better result can be achieved if you first design then language (or use an existing one) and just implement libraries to do what you want. A good example of this is Emacs.

Greenspun's tenth rule: Any sufficiently complicated C or Fortran program contains an ad hoc, informally-specified, bug-ridden, slow implementation of half of Common Lisp.

Incidentally, I haven't encountered much gnuplot use nowadays. Maybe 10 years ago it was pretty popular in academia, but most have moved onto using Python and matplotlib for plotting, even if the models are written in something else. Matplotlib is truly terrible, but at least it comes with a sort of acceptable programming language.

Tangentially related: I've been working on a plotting tool (https://github.com/LaurentRDC/pandoc-plot) that supports many plotting toolkits. I recently added support for Plots.jl. I can't believe how SLOW it is to get from running a script to getting output. 10x slower than matplotlib, 100x slower than Gnuplot.