Here's my particular problem with "too easy" -- and that problem is that it's usually not a problem for most of the people at the table.
I'm serious. I'd say that for every gamer who enjoys being challenged and threatened and wanting a shot at losing it all if they're not on they're toes, there are at least three more gamers who pretty much want to show up, be badass (regardless of their metagame or table-specific efficacy), and brag about the cool loot and powers they get. Now, the latter group of gamers tends to not specifically ask for a Monty Haul power fantasy. They want to have the illusion of challenge, even though a lot of people in that group don't do the hardcore rules analyses and min-maxing and creative theorizing the former group of games do.
The thing is, when the game is accidentally too easy, the latter group is still very satisfied as long as it doesn't get completely out of hand. A DM who tweaks the base assumptions of the game to have less of a 'Chicago Bulls in 1996 vs. the rest of the NBA' setup risks stepping on the toes of and disempowering the latter group. And while it's ironic that the latter group would rather have the difficulty slider tweaked off-camera and by neutral game designers than with a DM who can actually see what's going on in real time, it is what it is. D&D's a complex psychodrama that takes pains to provide the illusion of difficulty without actually being unduly difficult. And it's really difficult to avoid piercing the illusion when you're tweaking on the fly.
Now, like I said, this problem is a lot less pressing than a game that has one of those other difficulty problems I mentioned on the last page. So I'm not going to raise a big stink about it. I'd just like for people to see where some of the other '5E D&D is too darn easy!' people are coming from.