1. DM has to be able to pull an elephant out of his ass at any moment because someone might do something he forgot they could do. ..... you can spend 3 weeks tuning the encounters to prepare for the parties abilities and one mid to high level ability can screw all that tuning up.
I don't care if players defeat my enemies. I mean, I kind of expect them to. And I don't care how. Nor do I tune encounters for weeks. I don't try for "the perfect fight". I generally crank the dial up a few ticks past their last fight and move on. I sometimes think "I wonder how they'll survive this" and wait and see.
They don't know if the fight was supposed to be easy or hard. Did I intend that? Who knows. And don't care, as long as we're all having fun.
Plus I am perfectly willing to kill an entire high level party in a fight....because it doesn't end the campaign. It just slows them down and steals their gear. The clones get out of their vats, pull on their backup gear and head out.
2. High level games if you play in campaigns generally have consequences.
Yeah, low level ones have consequences too. And honestly, death is less of a consequence at high levels.
or the Paladin get the uber relics and becomes completely invincible
This gets to the fact this edition doesn't identify what "balanced gear" looks like. In 3e there was a chart. You might not like it, but it provided guidelines. Which also provided, indirectly, rules for giving enemies gear. Lots of +3 Widgets had to be pried out of their previous weilders' cold dead hands.
....
or the one secret evil character kills everyone and walks away whistling into the night.
....
It takes tons, and I means 100's of tons of effort to make sure the characters all have thier niche
This falls into my "don't play with jerks" table rule. Characters can evolve and grow, but don't try to powergame the uber character. And no secret evil characters. My games have had very clearly known evil characters, but they are team-oriented evil. Oh, they skim some a few extra jewels off the top and are willing to kill that villain the nicer members would negotiate with but they generally agree with the party's goals even if they think the methods are "soft".
PCs don't actually want to thwart the party. Those become NPCs.
But at the same time at that level every single character at some point is going to take over a scenario and single handedly "hulk smash" your planning and win far faster than you thought possible. And you have to remember at High level's that's the game as intended.
Imo that's the game at all levels. The players surprise us DMs. I'm all for it. I count on it. I don't know how the players will win some fights. Sometimes they realize they should run away. Sometimes they win big. Other times, a wet clone pops out of a vat.
4. Too many people have only played high level where the DM kneecapped everything
Yeah, this misses the point.
Be happy as a DM the party dosn't have to slog through forests for days. Lean into accelerated timelines. Have fun with the teleportation. Set weird traps, like a painting of a place the PCs need so they can teleport somewhere they have never been and have it be mislabeled so they go to the wrong place or add a Glyph of Warding in the painting that casts a Seeming on the party so they look like villains on arrival or maybe Mass Polymorph as birds so they fly away in different directions.
6. Another problem of High level games are the guys that think the bad guys doing the same kinds of things the PC's will do is lame and unfair. .... Was it unfair hijinks when Sauron Froze the mountains and forced the party to go through Moria? Of course it was nothing is fair at High Level.
Also falls under "don't play with jerks". Players should be prepared for smart villains. Villains are evil, they will do the stuff players do plus more horrible things.
Like turning your family to statues and hiding them in a permanent Nondetection field. Or even turning their own family into statues and hiding them in the Nondetection to "protect" them. Or maybe it's an elven "hero" who rather than killing "villains", simply "time shifts" them by a century, making the victim start from scratch with no resources.
Sometimes at high level play "antagonist" is more appropriate than "villain". Nothing like a determined 3rd level paladin to flummox a party of heroes.
Unless someone cracks what they tried to do with the epic level handbook in 3rd or pathfinders Mythic Paths (which are much better but still really hinky) I don't think High level play will ever be a large part of the games played.
I agree. It's a self-fulfilling prophesy that people won't play high levels if every GM had to figure out high level play on their own.
I find it sad that the original WotC stand-out product was Primal Order, a capstone meta-system for running gods on top of other games, like 2e. I think by the time the ELH was in development for 3e, the pre-TSR WotC designers had cashed out and moved on.