Currently in gnuplot, one has to resort to some mild trickery (a la the last demo on this page: http://gnuplot.sourceforge.net/demo_4.6/layout.html) to get things such as xlabel, ylabel or the key for a multiplot, especially if you are picky about getting the plots the same size. It would be nice to be able to specify these in the same way as for regular plots, e.g.
set multiplot layout 4,1 title 'My many plots' set multiplot xlabel 'Overall xlabel' set multiplot key
In this setup, the
multiplot [key|xlabel|ylabel] commands would automatically adjust the margins/size of the multiplot as the regular commands do for regular plots. The key could accumulate labels from all the other plots, possibly with an option to not include duplicates.
I understand that this may be tricky to implement for a number of reasons, but it is my and my colleagues' main frustration with multiplot.