Is there a way to resolve the fact that a lot of players want their martials to be Aragorn, but at high levels they're expected to fistfight a balrog?

Which Aragorn can't do, it's simply not that kind of story. And wouldn't be as good if he could.

My point is that a lot of times the fantasy is "down to earth guy who keeps up with Gandalf despite lack of fancy bullshit", but the problem seems to be that as levels get higher you are genuinely entering territory where you instead need to be Heracles to compete, going to to toe with dragons and getting all your blood back by taking a short rest.

Oftentimes I hear "solve it with magic items!", but while some love it others don't want their power to come from an external source. The wizard and druid certainly don't need the magic items to cope with a world of high powered fantasy bullshit, they're off teleporting and scrying and whatever under their own power.

Is this solvable (outside of simply not being an issue for some people, depending on what they want from their character) or an innate part of the equation?

Feanor can fistfight 7 balrogs at the same time…

Indeed he could, but while I've heard Aragorn used as an example of the desirable feel of a character's power numerous times I've never heard someone say Feanor.

The reason for that mostly being that there's no disconnect if say Fingolfin is your inspiration, he can go toe to toe with a balrog with no dissonance.

High levels martials have no problems fighting a balrog/balor. If they want to not be able to do that, don't level up.

Magic items are part of the game. An expectation, not a crutch.

I mean, you said it yourself: "sometimes, the fantasy your player wants is a normal guy". No, I don't think there's a way to fulfill that fantasy if it has to be fulfilled simultaneously with "The just-a- guy is kickboxing tripods from War of the worlds" - but why would you want to?

If your party is mostly super humans and one Just-a-guy, Just-a-guy is probably killing the lich's minions and leading the enslaved townsfolk to safety while the superhuman go wail on a would-be god. Not because that's all that can be expected of him, but because he's just a guy, and so are the townsfolk.

My partner and I were thinking about this, and we would love to try giving a second subclass to martials, but of course it should make sense for the base class to have it, thief for rogue, battle master for fighter, champion for barbarian (a homebrew subclass) and so on. We haven't tried it yet, so we don't know how broken it is, but it sounds fun to try at least once to see how it goes. I must add that our kind of gameplay isn't 100% following the rules, or rather we mix and match 5e and 5.5e

I don't get the question. DnD isn't Lord of the Rings, despite taking lots of inspirations from it. If people want to play more low fantasy characters, they shouldn't be playing DnD. Or at least, not 5E.

This I think is primarily why Martials do fall off in later levels, I actually do think it is intentional to a degree for this very reason

The only logical balance I can think of varies depending on the class, but having the martial be more nimble, having better survivability, extra attacks are a nice way of doing extra damage to not have some guy one-shot a balrog as you say

Realistically I think monks are the biggest issue with suspending disbelief on the topic as they are often literally just punching a dragon or something equally difficult to sell

I mean couldn't you just not have the campaign go up to high levels? Because like characters are going to get stronger as they level up, that's just how leveling up works. If someone wants to play an underpowered martial who could never defeat a dragon what they're looking for is a low level campaign with more mundane threats

Didn’t Aragorn summon a whole bunch of ghosts or something?

But yeah you can’t maintain “I’m a normal guy” forever eventually you need to be a badass

I feel like that's just not fair for the player, everyone is playing to be in this epic fantasy world and just because you decided to play martial it means you don't get to be as cool or powerful as a spellcaster? I feel like WotC is being lazy or even worse, favoritism to spellcasters and leaving martials behind in power scaling

If your goal is LotR the answer is simple - the campaign ends at lvl 10.

Not every story needs to be a high level one.

Frankly LotR might even only be a 1-5 story - back in the 3e days it was common to assert none of the heroes (including Gandalf) did anything that couldn’t be done by a level 5 party.

Conversely the older versions of Arthurian tales are absolutely lvl 11-20 campaigns. The knights of the round put anime to shame with their insane feats.

Pick a level max (and min) based on what kind of things you want the players to get up to, then stick to it.

I think I missed the scene where Aragorn had fisticuffs with the Balrog. Was that in the extended version?

Seriously though, your comparison is way off. In the DnD since, Gandold would have been an NPC/DMPC. He had no character advancement until he became Gandolf the White. Also, the rules for unarmed combat in DnD are terrible unless you are a terrible.

This is nothing more than another martial/caster disparity conversation and the only one that can mitigate it to any degree is the GM running the game. DnD IS a game that includes magic, so one of the tools to help balance things is magic items. If you do not like any of my points, then you are playing the wrong game, my friend.

I mean, magic items are here for a reason. Frodo got hit full force by an Ogre/Troll (dont remember how it is called in LOTR) and its little Mitrhil chainmail save its butt.

Give your martial a Sword of Killing Balrog and a Shield of Balrog protection (I am joking but you get the idea)

I think I missed the scene where Aragorn had fisticuffs with the Balrog. Was that in the extended version?