I'm not looking to strawman here, there are people wanting the option to pick a martial with a deeper pool of choices and I'm not going to conflate you with the occasional troll who wants to literally be Goku.

But for those who've put some serious thought into it. Experienced what they feel is more suitable martial gameplay in other editions or games, or have ideas for how it could be done in a better feeling way, or can articulate what's not working for them in 5e. What could they release that would have you agreeing that things are now in a good place?

Sure, Season of Champions turned out not to be martial books which is sad considering Arcane Unleashed did turn out to be a caster book, but there are releases further in the future.

Tome of Battle.

Round by round choice of resource expenditure that can be refreshed and do more than just being riders on the attack. Stances. Reactions that aren't just opportunity attacks.

4e Powers

Yup, the Book of Nine Swords. Can't be that hard, WotC. Just do it already.

They have literally done it before too, and it was very well received all around.

Well, firstly...

>occasional troll who wants to literally be Goku

I don't think there's anything wrong with wanting to be super powered by level 20. Obviously Goku's level of power doesn't work for a TTRPG without the whole system being written around around it, but enjoying that fantasy is not problematic. I also think wanting a fighter to be in the same ballpark as a wizard at any given level is totally fair and a professional TTRPG company that can't delivery on a minimum level of interclass balance has failed their job.

For me, I'd want martials to have a system of martial "cantrips" and "spells" fueled by "spell points" that give them the same level of competent and versatility that's enjoyed by spellcasters. Call them powers, exploits, maneuvers, whatever you want. Using the half-caster classes (paladin, ranger) as a baseline would work: they'd have the same weapon damage sustain as those classes while having powers roughly equivalent in potency to a half-caster.

A system of special actions that they can choose and need to spend a resource to use that is modular enough to allow for extra additions as new books are released. I think the closest to that are Laserllama's exploits

Once per long rest Feats of strength for higher level 18+ strength characters

I want to be better at fighting than a caster at higher levels

Playing another system, but that would mean they would have to stop crying about it, and they'd die if that happened.

A new system specific to martials thst give combat and out of combat abilities.

When they get acess to this they start put with 2 options and end with 6

Half caster/martials get 1 at the start and end with 3.

About 20 universal ones for all martial classes for combat

About 20 universal one for all martial classes outside of combat

10 class specific options for each martial

And about 4 options specific to each weapon

Nothing, because I enjoy the game and have no issue with the phb.

Middle and high level Weapon Masteries and Fighting Style options would be a good addition and wouldn't require any real changes to the base martial classes. They've built in the ability to swap those as you level up, so this feels like the next logical step.

So, maybe they'd require you to have X number of levels in the class that gave you the mastery/style in order to take them and they would give you a bunch of power and versatility right as the martial/caster divide really starts to ramp up.

Stances that change how you approach a fight and are impactful. Fighting styles that are an actual subsystem, not just a bonus point of damage. Maneuvers that go up in power as you level. Early maneuvers are things from the battle master list. Late level stuff let's you do stuff like aoe attacks. Supernatural feats of prowess. Not just the strength/athletics stuff but also skills. Reactions that aren't just opportunity attacks.

I love martials and they are fun. They do lots of damage to single targets and they take damage, they fill the gameplay niche that they are supposed to. I would just like them to have more. More options, more to do out of combat and cool new things. I also want more sub classes that go in different directions and for the designers to not be afraid to let martials do things other than attack.

What we really need is a subsystem that can tack on that gives martials options but also has a resource cost, a martial mirror to spell slots. The designers are getting there with giving options to spend hit die on doing cool things and that is probably the direction I would lean.

I don't think the issue is wanting to be Goku, it's wanting that as a baseline option for a class and also with the stipulation that nothing can come from magic or by reflavored.