I have my own house rule where any noncombatant NPCs just 'get' 1-3HD and what ever modifires I want to skills and checks... including any/all special features.This is concept is why I think 6e with have triple prof or mastery but for NPCs only.
Another way that D&D changed is that it tends to mechanically fill holes over time over just having DM fudge stuff forever.
I have (in an upcoming session PCs have not meet them yet) a pair of gamblers who have +9 to dice and +12 to cards on one and oppisite +12 on dice +9 on cards on other... and BOTH have skill mastery so they count anything 1-9 as a 10... but they have 11's and 12's in all stats and 2d8Hd... one of them has the lucky feat.
two of the 5 characters like to gamble and will find playing them HARD... but if they end up wanting to just beat them up and take back the winnings that would be Super Easy, barely an inconvenience.