I would question whether the surveys are a useful proxy for satisfaction. In other words are the surveys that indicate dissatisfaction with a Champion really reflective of the playing population or are they a biased sample reflective of the people who spend the time to take the survey?
So then, you admit that the process they've been using
since the D&D Next playtest could have been skewed--damaged--by having biased samples? That their survey design sucks? That they just might have listened only to a skewed, unrepresentative few who demand things out of step with what would actually make players in general happier?
I can say confidently a lot of people are going to be dissatisfied with a more complex fighter
Really? Are you
really sure about that? Because the explosion of comment and criticism that happened on this forum
and others, in the wake of 5e's launch with nary a complex fighter to be seen--that the "Warlord Fighter" promises had manifestly failed to pan out--seems proof enough to me that there's a dedicated, serious fanbase there.
Not every subclass or class needs to be made for every person. Some things are made only for the fans of that thing. This should not surprise you in the least.
and even more will be dissatisfied with a more powerful fighter that is closer to a full caster at most levels in terms of power level.
Then show me the data. I know you've got this frankly bizarre argument that Fighter players want to play weak, incapable characters while the spellcasters rule the roost (despite the mountains of evidence to the contrary, including from WotC itself), so if you're going to be so confident in saying that, give me your data.
Yet these are the things that people are dissatisfied with about the champion.
They're dissatisfied with the Champion because
it sucks, because it is a
bad subclass, not because the idea of a simple, focused, no-frills subclass is bad.
Champions derive essentially all of their benefits from three things: Remarkable Athlete, an expanded crit range, and getting an extra fighting style. Of those three, the fighting style is the only vaguely-useful benefit, and that only for having both Archery and your preferred melee style. With the way actual 5e is played, parties rarely if ever face more than four combats a day--and often get less than two short rests on average. But in order for the Champion's extra damage--which
purely comes from rolling additional dice, due to how 5e crits work--to keep up with the likes of a Battle Master, they must get on average enough extra attacks per short rest to match the BM's superiority dice per short rest.
Consider 11th level, when the Fighter gets 2x Extra Attack. Even if we are incredibly generous and assume three combats per short rest and
six rounds per combat (which is absurdly long by 5e combat standards), a Fighter is only getting 3x(6x3+3) = 61 attack rolls per short rest. That means the very best an 11th-level Champion is getting is a bonus 3d12 per short rest--and only if she's wielding a greataxe. Meanwhile, Battle Master maneuvers are granting a floor of +5d10 damage per short rest (and since most are "when you hit with an attack..." rather than "before you make an attack..." you are guaranteed to get those dice as long as you actually use them.) So even when we stack the deck ridiculously far in the Champion's favor, the Battle Master is still ahead. This isn't even comparing to spellcasters; it's a comparison purely within the Fighter class itself. Compared to a spellcaster in the typical way 5e is actually played (where spellcasters, quite rationally, lobby to take long rests as often as possible), the Champion is simply left in the dust. The comparison only gets
worse at earlier or later levels, despite both the further-increased Champ crit range and the addition of further Action Surges and Extra Attacks for all Fighters (which have no meaningful effect on how much extra damage Battle Masters can do.)
The whole point of a basic option is that it's supposed to be reliably better in general, shorn of detail and context. The Battle Master should not be
generically outclassing the Champion just by using its basic tools in the most basic way possible. BMs should have to work for it--starting out a hair behind, but getting a leg up
if they happen to have the right maneuvers at the right time. Champion fails at this. Doubly so because Remarkable Athlete is and always has been a joke, and having a second fighting style, while not at all a
bad benefit, is nowhere near enough to hang an entire subclass upon.
ALL of the really really fundamental archetypes of 5e should have at least one "just really basic" option that is actually
good, meaning, one that actually achieves design goals appropriate to that aim. For example, such options should be easy to use, while still remaining engaging and exciting--it should feel
great to do whatever simple, straightforward thing that class does. There should be a simple spellcaster, that blows up enemies and has some basic "magic trick" or two. There should be a simple thief, who has feats of derring-do or Errol Flynn-esque panache and style. There should be a simple warrior, who just kicks ass and takes names, "I think Halo is a pretty cool guy, eh kills aliens and doesn't afraid of anything." And there should be a simple priest, who can get their god to do them a solid now and then, and reattach your face when something has torn it off.
5e has not generally done a very good job of the design on this front. It has
attempted this with only two of the three above (Life Cleric is, bluntly,
not simple enough), and those attempts were pretty blatantly lackluster, albeit for different reasons. (The Champion is simply a bad Fighter subclass when judged against its fellow subclasses, though Banneret is a close second; the Rogue chassis in its entirety is simply not that great, and only rarely allowed to exceed those limits.)