We're getting side tracked. Wizards do not represent all spell casters and champions do not represent all martial classes. Wizards are not in serious trouble without their spell books because all it does is stop them from trading in prepared spells and using rituals until it's replaced; a pain to be sure, but not crippling to the class by any means.
I disagree that without feats there isn't much to fighters. I believe this for multiple reasons:
As i said before.... play a champion with JUST heavy armor mastery (not a "choice" feat.. its always on, minimal "thinking" required and the Shield Mastery Feat... always an option, can use any time, no limit on uses) and then play one without those feats...
its a night and day difference in survivability (-3 damage seems small until your hit 10 times and saved 30hp of healing time/spells/potions) and flexability (shove as a bonus action, cover-like bonus from dex save spells and effects.. the most common save)
1) That has no impact on anything in the class progression other than the two bonus feats/ASI's that would be used for ASI's which improves skills and saving throws. It's perfectly viable to invest in CHA or WIS on a DEX built fighter for better skill capabilities.
and not pick up new skills along the way... proficiency bonus is huge, without feats they will always be nearly passable when using those skills...
saves are nice but again, without the proficiency bonus (another choice though feats) your "mhu".... a +2 to charisma save is not going to do much against a DC: 15 save or suck effect... a +5 on the other hand...
2) Not all fighters are champions. Champions are the simple option and benefit from multiple fighting styles, ability check bonuses, improved critical accuracy, and survivor; feats aren't an inherent part of the subclass benefits. If a person doesn't think that the intended simpler option in the champion is appealing then they can play a battlemaster, eldritch knight, or different martial class completely. Monk or Rogue for some good options.
see above, even if you choose "simple" feats like gaining skills or packing up a new save or gaining DR: 3 against melee attacks (heavy armor mastery) you are still light-years better then a stranded champion
feats do not always = complexity so this argument falls flat.
3) Since not all fighters are champions the other subclass key features like maneuvers and spell support are still there.
see above
4) Fighters do not have a long list of basic powers but they also do not just swing attack. Basic attacks, grappling, knockdown, and push are each standard attack options that use a single attack during the attack action. Players who play fighters just swing by choice. Those attacks increase in permutations as multiple attacks increase, and battlemasters or other classes with similar abilities are simply better at them. It doesn't matter if these are handled by stating them in sequence by the player or if the player decides to "codify powers" by stating, for example, that an 11th level fighter gets "grappling pin attack", "swing attack" ([W]+STR to 3 targets within 5 ft range), or "battle flurry" (choose 1 target, make 3 basic attacks against that target). Many of the codified powers that existed were upgrades of existing options that emulates multiple attacks. A person can go through the options and list several with snazzy names in 5e for similar effect and a whole lot of at-will "powers". Another option is to use the ready action and see what a person can do using his or her reaction; that how a person jumps in front of an eldritch blast and take the hit meant for someone else, for example. It doesn't bother me to force a wizard back 15 feat with 3 consecutive shove attacks, through an arch or doorway, and restrict his line-of-sight; that's a standard fighter option. Between standard attack options, standard options aside from attacks, using items or equipment, and using backgrounds and skills outside of combat the character has several options even if he's a champion fighter.
I broke down before how dealing damage is commonly a far far better option then special maneuvers, unless you can get away with using them as a bonus action. the only acceptation is high AC targets, shoving them to get advantage on your next 2 attacks may be worth it.
but most of the time you want to take the target out so it stops dealing damage... the more actions you take away from the GM the better is it for your party
On that same note from item 4, battlemasters don't need to use maneuvers or superiority dice to use those listed options. Battlemasters are better at such options by also applying maneuvers on top of damaging attacks as a bonus and possibly on attacks to which those standard options won't apply. They can also mix and match standard attack options with superiority dice maneuvers if they so choose. This means they don't run out of superiority dice as fast and that they have more permutations available to which the action may be applied.
Using the standard rest system means battlemasters start with 1-2 maneuvers per combat encounter. Usually 2 but at 6-8 combats and 2 short rests it can vary a bit. The end up with 2-3 per combat encounter with a guarantee one will be available every combat. They can do things like trip a griffon with a bow while it's flying, trade in an attack to grant another attack beyond their reach within sight and hearing that can potentially go to a stunning attack/smite/sneak attack character, or grant half moves without opportunity attacks. If they action surge they can spend up to 6 dice on maneuvers in a single turn in various combinations. Then they can apply their free artisan proficiency for a nice lifestyle while working on political influence from within the guild with some CHA investment to go with it.
see what I said above, the CHA investment is really not worth it unless you have a CHA skill.
how do you get one after character creation 1) take a year to learn it... if the GM is nice 2) feat 3) mutli-class
Fighters are great in 5e. They just are codified on the same power structure as other classes because that's not the standard for any class.
never said they were not a good class... but they are far far far better when you allow feats.
they get more bang for the buck from feats then any other class because they can get more of them