That was just party simplified down to 1 character to showcase why nova potential is of significant value. One party has little nova (Fighter has Second Wind and that's it), while the other one has very significant nova (two 1st level spells).
This example can be extrapolated to party level, but showcasing it with a simple, practical example is infeasible within the context of a single forum post due to the amount of variables and inherent complexity of the setup.
EDIT: I realise that two subsequent fights with individual Orcs would do the job better. The at-will party will probably beat the first one but at significant damage and fall to the second one, while the nova party can nova both and likely take 0 damage at it.
Aye, that would be the goal. Probably necessary to split the ranking by tiers and have some kind separate values for endurance and peak potential (somehow accounting for long duration spells, at-will abilities, more restricted short rest abilities and long rest abilities).
I'm still pondering the details of how to go about it hence this thread: to spitball and critically assess different options for quantifying class peak and endurance (not necessarily those exact things and not necessarily with only two values) and their strengths and shortcomings.