fearsomepirate
Hero
My own analysis of AC by tier (considering which monsters below to which tier) yielded roughly the following:
Tier 1: average AC 13
Tier 2: average AC 15
Tier 3: average AC 17
Tier 4: average AC 19
I don't have the spreadsheet anymore, but it included the MM, VGtM, and MToF, plus some extras from adventure modules and settings books.
If you consider, in their main "thing" PCs are typically +5, +7, +9, and +11 in their attack bonuses (discarding magic items and features) at each tier, respectively, (due to ASI and/or proficiency increase), this holds that an 8 or better is typically needed to hit, or 65%, across all tiers in 5E.
So, that is why I assume a 65% hit probability.![]()
Seems accurate to me. Which also explains why, as more things come online, everybody is nearly always hitting.