I suspect GP is referring more to complexities in the gameplay, not loopholes (though I'm sure 5e has fewer of those, by nature of being less rules-heavy and mo

I suspect GP is referring more to complexities in the gameplay, not loopholes (though I'm sure 5e has fewer of those, by nature of being less rules-heavy and more reliant on the GM's interpretation). For example, weird corner cases like grappling rules have been greatly simplified. So have skills, weapon selection, and combat rules in general. As late as 3.5e and Pathfinder, you could easily spend 5 minutes figuring out how to resolve a single 6-second action according to the rules. Say I'm grappling someone (complex rules) and move them across rough terrain (5-foot step or not?) while threatened by an enemy combatant (attacks of opportunity) with while under a Bard buff (pluses to defense)… figuring out who attacks whom when and how can easily involve flipping to many different sections of the rule book. Whereas in 5e half those rules don't exist and the remainder are simplified. My understanding (not from experience) is that previous editions had even more complex rules than 3.5e, and 4e simplified the rules in the "wrong direction" (away from role-playing).