Chaosmancer
Legend
There is no issue with this. In my experience wizards items generally let them do more of the same, rather than be much better at what they do. Unlike a fighters items that objective make them better at things they do all the time, like hit things and deflect attacks.
... Yes? I mean, you literally just gave the fighter items to boost AC and their to-hit bonus.
I could give the wizard at-will telekinesis, defense against arrows, the ability to just automatically deal damage, more options to simply dominate the fighters mind, regeneration. Or, I can just do what you did, and increase the Dragon's AC.
Is there a specific effect that will absolutely shut down the fighter in a duel? Probably not. Most items have saves of DC 15, but this fighter hasn't seemed to invest in wisdom, so I'm sure I'd get him with something.
As I said earlier and made clear in my post GWM was an alternative to the sword and board fighter. Either take the damage and whittle the dragon down fairly quickly with sword and board, or Great weapon it and break concentration. Both are possible.
Great Weapon is a poor choice though, as I showed.
And, even if the fighter turtles up and uses sword and board, you have to remember all of the hp of the dragon he is cutting through? None of it is the wizard's health. It is all temporary hp.
All this is looking at the wrong question though. 20th level fighters are not dueling 20th level wizards in isolation. They are both approaching the adventuring day at the same time, and the fighter will consistently out-fight the wizard in the foes they face across the day. D&D isn’t about single spells changing the adventure, if it is then the adventure writing is sloppy. It’s generally about a series of encounters.
Really? We literally have a discussion about needing to go to a different plane of existence. That cannot happen without magic.
At high levels:
How did you learn where to go? Usually magic
So, how does the party get to the encounters? Usually Magic
What happens during combat? The wizard is using magic to control the battlefield, buff the fighter, debuff the enemies or just kill them.
What happens out of combat? The wizard is using magic to solve puzzles, reach places, find things, and bypass challenges.
What happens in the climatic fight? The wizard shuts down the encounter with a powerful spell.
Sure, maybe the fighter... I don't know, did a strength check that was really clutch? Knew a person to talk to? But casters define the game at high levels. Heck, even at low-levels. Murder mystery games are hard to run. Not because of fighters, but because of casters. Can't just put the McGuffin in a place that is high up. Not because of fighters, but because of casters. Need to know what someone is thinking? Casters can do that. Need to find a missing person? Casters can do that. Someone is dead and their body disintegrated? Casters can fix that.
The only thing in the entire game that a caster cannot do, is deal with anti-magic. Literally, you have to remove magic for them to not potentially, at some level, have an answer to what you have just done.
Why is the Tarrasque such a joke? Because it is essentially a high-level fighter. All it can do is make physical attacks and run. That's it, so it can be taken out by a mid-level party.