I'm not sure though why they called it ScalingFunctions, I thought my "AxesScaling" was nicer, but well, slowly they use it in more and more functions
Yes, I also wanted a 'ListDateDatePlot' (to track an ETA over time), which would be really easy if ScalingFunctions was implemented throughout the system.
I think a central website for Mathematica requests would be very nice, where people can vote on them...
Though hope is not lost; for example I proposed GeoDistanceList in this big feature request topic, and they made it (and it is awesome)! So they do listen (or it is coincidence of course).
The plot legends are still not 100%, because a plot with PlotLegends is not a Graphics object... so combining them (subplots) is very tricky as imagepaddings and stuff don't work as you think... so I end up using Epilog -> Inset[legend] constructs to 'embed' the legend in the Graphics...