This again is the fascinating bit that makes me think the person writing it is an ever-DM or never plays wizards in a game setting.
Firstly AC20 is achievable for 1 round and to be honest AC 20 isn’t amazing at anything but low levels. You can expend the next round by using it again but then you’re burning through two slots per round plus the one you used to get the mage armour up. Sure it’s useful for avoiding the occasional hit when you’re at the back somewhere, but wading into combat and soaking damage.I don’t think so. Not to mention that when you do that any ranged attack spells are at disadvantage to hit.
Really? ANY ranged attack spells? Well, be still my beating... oh wait... Hmmm... aren't there only like... six spells other than cantrips that use ranged attacks? And don't most of them... suck?
I've got to be wrong about that, since I don't know what I'm talking about... And I was! There are 10.
Chromatic Orb (1st level, quickly falls off)
Ice Knife (1st level, decent but falls off)
Ray of Sickness (1st level, sucks)
Witch Bolt (1st level, sucks)
Melf's Acid Arrow (2nd level, sucks)
Ray of Enfeeblement (2nd level, sucks)
Scorching Ray (second level, actually decent)
Storm Sphere (4th level, unaffected by your point)
Wall of Light (5th level, unaffected, and kind of sucks)
Crown of Stars (7th level)
So yes, all of those spells out of your hundred something options can't be used in melee... well except the two that can.
Now, as to the 20 AC. Firstly, 20 Ac is still good. It is the best non-magical AC possible without using class abilities. A Rogue for example maxes out at 17 AC. A monk needs to reach incredibly high levels to get 20 AC. It isn't bad. But also, you assume it needs to do more than protect them for a single round. But Wizards can win entire encounters with a single action. They sometimes only NEED a single round. Being able to protect themselves for 1 turn can be massively powerful for them.
Secondly no wizard goes into combat with 1 damage spell and one control spell memorized. They just don’t. Mainly because most spells are circumstantially useful. Fireball does not work when the room you’re in is full of your own people and disintegrate doesn’t work when you’re fighting many creatures. Etc etc. every spell has its own weaknesses and strengths, often because of damage type. So please don’t suggest that wizards have space for all these utilities because they only cast fireball and Magic missile. If they do, they’re clearly leaving the martials to excel in combat and as I said before combat is a huge part of D&D.
I didn't say 1 damage spell and one control spell period. I said one per level. Heck, you literally listed them right here. Magic Missile (1st), Fireball (3rd), Disintegrate (6th). But you are very unlikely to see a wizard take Erupting Earth, Lightning Bolt, Fireball, and Tidal Wave. There is too much overlap and that would be silly of them.
Seriously, pay attention to the argument before you try and disprove it.
Wizards can have a solution to most problems, just not at once and not on the fly. There’s nothing wrong with that. Magic allows characters to fill gaps in the party, that is a good thing. Don’t forget it comes with an opportunity cost though and that’s the trade off.
Six Encounters per day doesn't just refer to fights, it also can refer to challenges. But, let's say during a full day there are 10 problems that need solved.
A 12th level wizard likely has 17 spells prepared, and any of the 28 spells they know that are rituals are instantly available. Let's say six ritual spells. That is 23 spells on the docket. Meaning that they have double the number of potential solutions than problems that can be expected. And we know multiple of those problems are going to be combat. Again, every wizard knows that combat is a thing that is going to happen, and combat encounters make up the majority of the situations.
The One DnD wizard can also modify their spells to make them more versatile, and has a ritual to change their spells for any possible spell they can prepare, effecitvely making all 28 spells available.
Does a wizard always have every single solution to every single problem? No, probably not. But they are probably going to be able to trivialize about 5 of those problems. Maybe more, maybe less, but about half of the problems for the day the wizard is going to be able to, just from statistics, solve.
How many times can a fighter solve a non-combat problem without a roll? How many fights can a fighter win in a single action on a single turn? Zero. None. And any situation where you can say "but a clever fighter could use [X] to do [Y] and therefore solve the problem!" Like using rope to climb a tower.... a wizard can do that too. A clever wizard can do anything a clever fighter can do.
Even if we accept that not every wizard can solve every problem every time... they can solve most problems most of the time, just by knowing what they are getting into. And fighters can't. Barbarians can't. Rogues can't. And this is a major disparity.
