I dont know if this has been a topic for discussion before around here, but I recently thought that some AOs are much better to beat for the investigators in final combat, if they engage them in a greater group.
So I made a graph to compare this effect:

This shows the mean minimum successes that every investigator has to achieve during a single round of the final combat.
Some assumptions were made: No investigator is devoured at the beginning of final combat. Every investigator has a total maximum sanity and stamina of 10, reduced to 8, which results in a maximum of 6 combat rounds against Cthulhu.
The values for Zhar are middled due to the fact that the investigator with the zhar-token just has one hand for the fight. Probably the number of dices to roll for an attack with only one hand are not just the half of the number of dices with both hands but maybe a bit higher, but this is a necessary simplification.
Of course this chart cannot be used to compare the difficulty of the several AOs in final combat, because it does not take in account the different immunities and combat modifiers. But they are still the same no matter how many investigators you play, so I think they have no effect if you compare the strength of an AO against a tiny group of investigators or against a large group.
What do you think about this effect?
It may be thematically fitting but it unbalances the game a bit, I think...