Sv being J/kg is kinda a lie on that chart: it's more accurately the amount of radiation that would provide biological effects equivalent to that amount of some standard spectrum.
I don't really see much of a difference between starting with time and frequency: we define all of that by "one period of <some lightwave>" anyway, so we essentially start with frequency. We also divide by units of surface area in quite a few places.
Re charge: amusingly 1 mole of electrons is something like 96 kC.