I think the problem here is that there is an untapped group of players who are not being reached by D&D.
Right now you have a situation where a player who wants to play a martial has to play a low-influence class. For these people thus they have to make a choice. What is, to them, most important? Do they want to play a martial, or do they want to play an influential class?
Arguing that fighters are good because they are popular misses the fact that a lot of people might make the deliberate choice of playing the class not because it is well designed, but because it is relevant to their character concept.
It's like when I played a battlemaster fighter and retired it because I felt I had no influence, I made another fighter and that time I made an echo knight instead. Why? Because I both wanted to play someone who hits things, I did not want to play a magic user, and I wanted to have more influence (Echo Knight still has less influence than casters, but better than nothing).
So like imagine you put maximum priority on wanting to play a martial just because. Now you have to suck it up and accept that you're not going to have as much influence as a caster.
My point is that that should not be a sacrifice that you have to make. You should be able to play influential martials.
I am talking about explicit mechanical influence.
Martials are less influential because there is an incredible array of mechanical ways of interacting with the game that are completely or nearly completely off-limits to non-casters.
These are more obvious:
- Inflicting blind
- Inflicting fear
- Being very very very good at something. The most surefire way to get out of a cell is to teleport out of it.
- Interrupting a caster casting a spell
- Being able to get somewhere quickly.
- Being able to resurrect people from the dead
- Being able to heal people
I think this is a fundamental problem with D&Ds design, and to a lot of players have become blind to the fact that large swathes of mechanics are out of reach to a large number of classes.
I'm not following what "influence" an echo knight has that I don't see in a battle master in your example. I think using the battle master's student of war ability gained at 3rd level to add a useful skill proficiency and also proficiency in alchemist's supplies is more useful than a 1hp echo because those alchemist's supplies can be used to brew potions during downtime on that fighter.
That fighter can produce basic healing potions in 1 day, common potions in 2.5 days, uncommon potions in 5 days, and has the ability to invest more time and money in more rare potions if the player thinks it's worth it.
The battle master maneuvers have several ability bonuses. The echo knight at the battle master can both use tactical mind on something like a persuasion check, but the battle master can have the bonus proficiency from student of war and add a bonus from commanding presence and use perfume for advantage on the roll crafted with that alchemist's supplies or either could just purchase the perfume. Conversely, a wizard spending a spell slot on charm person for advantage falls short in comparison.
While neither the echo knight nor the battle master causes blindness specifically, the main benefit of blindness is advantage / disadvantage and battle masters have maneuvers to accomplish that.
Battle masters have the menacing attack maneuver to create the frightened condition.
Being good at damage is something. Being good and taking damage is something. Another way to escape a cell is to break the door, or pick the lock, or pick pocket the keys.
Something that's also good at preventing spells is the ability to inflict the dead condition. Martial classes doing a lot of damage to drop a spell caster does wonders. Something else that works is a monk readying to stun a caster when they cast the spell thereby interrupting the action with the stunned condition, or just stun ahead of time. High level rogues can do this too with potent strike and the unconscious condition.
By the time high level casters can cast spells to travel quickly (which is nothing but a convenience) the high level martials can pay for the service from NPCs.
Is being able to resurrect the dead really more impressive than not dying in the first place because of more hit points and better armor? Again, this is also a service for which high level PC's can pay, or often the DM can side quest it.
Everyone can heal themselves with short rest HD expenditure, the healer feat improves on healing, and second wind is an obvious source of healing. Rally can grant temp hp instead.
You seem to be ignoring what martials can do when you make your argument here. There are obviously things that spellcasters can do that non-spellcasters cannot, but that's because it's a class-based system and each class has it's own strengths and weaknesses including spell casters. ;-)
