So you actually have this backwards - until high level the wizard will use his spells BEFORE the battlemaster runs out of maneuvers and the wizard will have less abilities to bring to the fight after he runs out meaning he is a wizard for a smaller portion of the day.
Noncombat the wizard is bringing rituals and the battlemaster is bringing his Alchemist tools and making poitions of healing, oil, alchemists fire, antitoxin and acid. The wizard might have a slight edge here but not an overwhelming one and not one to overcome the difference in combat. If you are choose something else as your artisan's tool, well that is on you.
This would be a great point for you if you used the Arcane Archer instead of the battlemaster, but the numbers do not support this hypothesis with the battlemaster.
The Illusionist has the Minor Illusion cantrip. They can do it all day long and whenever they want and they'll feel like an illusionist. The Battlemaster has no equivalent options. That's it, that's all I need to say to prove than an Illusionist can be an Illusionist all the time while a Battlemaster is that only part time.
His tools proficiency could have been gotten from anywhere so it's not something unique or linked to the reality of
being a Battlermaster, it's just a random perks they get that anybody could get with a little investment. Heck, you can learn tool proficiency with sufficient downtime according to Xanathar, right? So that 'feature' of the battle master is just worth like a month or training or however long it takes to get that. It's cheap as hell is what I'm saying.
Making stuff with Alchemist tools is very dependant on your DM and available ressources and... SURPRISE! Most of the stuff you make is
combat related. It has very little use as out of combat problem solving unless you want to burn something down.
Barbarians, on the other hand, are proficient fighters but less flexible. They are, however, much more useful outside of combat. If your DM rules iron doors are broken at DC 20, the barbarian stops needing to roll, period, at level 18 and automatically gets to DC24 by default, no rolling at level 20. Berserkers can force frightened on characters with relatively low wisdom at-will. They can intimidate a king with their presence and make negotiations easier. Totem Warrior has a sleuth of useful OoC uses like Spirit Seeker, Aspect of the Beast, and Spirit Walker.
They can't do all of the above because the above is unique to barbarians. There's nothing a fighter can do to imitate a barbarian's Indomitable Might, nor can they imitate Primal Champion.
They can't enforce frightened without an attack roll and they can't cast Commune with Nature.
They can acquire feats, but none of them let them do what barbarians can do. And that's okay, because they work on different fictions.
Now there's an interesting question: is there ANYTHING a Fighter does outside of combat that can't be replicated by another class? Is there a single out of combat thing that you can look at and say "Oh yeah, that's a Fighter feature."? Or is it all just skill and tool proficiency any random Rogue can get and be better at?
Use optional healing rules... Yes, there is an issue with the base assumtion of 6 to 8 combats a day outside dungeons. Take the slow healing option and it all goes away... and it is not even a house rule, because it is explicitely mentioned in the DMG.
I think those optional rules should be more prominently featured and discussed in the PHB.
And maybe a different default rule should be in place.
I'd be worried optional healing would just make magical healing even more powerful and important.
But in this discussion people are demanding completely separate new classes. That is far more major rule change than just tweaking an existing class. I really find this bizarre, the same is happening in the witch thread. "The existing class doesn't do this one little thing I want; solution: write a complete new class." Like what? Why? Just fix the one bloody little thing that was an issue in the first place! And of course these don't need to be just houserules, WotC would update/errata/provide new options for existing classes far more easily than write all these countless new classes people keep demanding.
I think the argument is that they've crammed way too many concepts into the Fighter class. If the Wizard, Cleric, Druid, Sorcerer and Warlock can all be separate class, there is no reason that every single 'guy with a sword' trope has to fit neatly into Fighter (or Fighter, Rogue and Barbarian). I've come up with 8 subclasses for my Warlord and I'm an amateur designer. Somehow the former trained soldier and the Chosen One who just picked up a sword are the same thing at level 1? Why should that be the case? I think the Fighter would benefit from being defined by its more formal training (compared to a wilder Barbarian and an underhanded Rogue) and another class could pick up the slack of the nobody.
has rendered the rest of the fight a fate accompli so their pals
That's 'fait accompli' btw