I found these graphs and stats about ACE:
Meaty presentation of the data in the context of global weather, and the last 40 years. To my eye it seems that this year has greater frequency of less energetic storms, but sort of a wash for total world-wide ACE.
Energy is energy, so why have tons of littler cells rather than few large ones? Does a big, well-ordered cell deplete the energy available and make littler ones less likely? Do lots of littler ones starve the system of the energy needed to organise a monster? If energy available to ACE were to increase, wouldn’t we hope for many smaller events instead of few large ones?
What happens if the energy available to ACE were to go unused? Does it get banked? How? Stored heat in seawater? Is banking the mechanism behind the periodicity observed between seasons?