Blue
Ravenous Bugblatter Beast of Traal
Wow, I don't think we play the same game. Or even read the same rulebooks.Given the loosey-goosey, "you're the GM, you figure it out" design of 5e, I doubt this will be even remotely an issue.
5e is never going to be a game where the rules just inherently work out of the box. That was, quite literally, one of the design intents, leaving a portion of the design for the GM to figure out. They're just adding new elements that also expect such.
5e chomped down so much on this. There's no Rule 0, and if you read the (2014) DMG where the DM is supposed to do what your claiming is extremely curtailed.
And frankly, it's run "out of the box" just fine for over a decade of multiple games, multiple DMs, as both a player and a DM.
As in, I have no reference for you to even make that statement.