This is one of the things that I genuinely don't understand. Other classes have mechanical class options for the social and exploration pillars. They are built into the class. The Fighter has none of those options now. It seems as if you don't care about balance in terms of what a character can do in a session, which I can see. A Fighter can take a skill to contribute to exploration (and even that is an optional rule, remember), but they will never be as good as other classes who do. From the last campaign I played in, they will never really be anything other than mediocre at those things. Why should that be the case?
And that's when I genuinely don't get why creating a new class that could do things in those pillars would somehow be bad. If we don't care about balance, why is a new class that can do more than the Fighter a bad thing? Or is it that the Fighter has some unique quality that means they can control other martial classes and what they can do? Let's say we did a Ranger that removed spellcasting and would be just martial. Would they now have to lose exploration abilities? I'm genuinely not seeing how this makes sense and I'd like to.
I'd really like to understand this, since it sounds lot like what WotC's designers are saying, and, if I'm being honest, that's poor design to me. So I'd really like to get it since I can understand the design choices of really just about every other game I've picked up over the decades. This isn't intended to be an attack post, rather a "I just don't get the perspective." And I'd like to.
First, I appreciate how you word you response. I feel like you and I are alike in that we're here to learn from others. Others who may or may not share our approach to the game. I know ENWorld has improved my approach to DMing over the last 6ish years.
TBH, I typically don't agree with the poster you are responding much but... I think I have a bit of common ground with them on this topic so maybe this will be helpful for you in your desire to understand what is likely a similar perspective.
First, at our table, players are not limited in the types of actions that they can propose for their characters. If it makes sense in the fiction and if there is no uncertainty, the action just happens. A Fighter wants to parley with a lazy Guard even though they don't have the highest CHA(Persuasion) modifier in the party? Why not? This is a game of make believe and story telling, not just a game of beating random numbers. (Note, I'm not trying to belittle anyone here who leans heavily into the crunch. I'm just saying it's not the only factor some tables find important for fun at their table. Sometimes actions can just succeed and we move on to the next challenge. Indeed, this is the approach of the Middle Path as detailed in the DMG pg 236)
Now, let's say this guard is a real stickler for rules and won't just let anyone past... but our 3rd level Champion Fighter has the Noble background and so has proficiency in Persuasion. With their 10 Charisma, our Fighter has a +2 to Persuasion. Okay, that's not as good as the Bard's +6 or the Sorcerer's +4, but this guard happens to be a social climber (or perhaps honors the social pecking order or...). The DM awards the Fighter with the Noble background Advantage on the check to try to sweet talk his way past. So... I guess where I'm going with this point is that checks don't happen in a vacuum. The DM creates these scenarios and presumably gives the NPCs Bonds/Ideals/Flaws/Motives and players, via their PCs, can try to discover those characteristics before going in for their ask. Maybe instead of a social climber, this guard is greedy or gullible or susceptible to name-dropping or... something else. At the end of the day, the Bard, despite their +6, just may not be the obvious or only choice to try to Persuade the guard. It might just be anyone in the party who slips the guard a gold piece or mentions the name of the local pit fighting champ or whatever. The DM is a
major factor here in how they set up such scenes. Math and probabilities need not be the end all and be all in this game we all love.
It's also worth noting that the d20 is a fickle beast. The Bard being 20% better than the Fighter at Persuasion doesn't really mean a heck of a lot when that roll might come up once or twice in a session. It's just not noticeable with such a small sample size. Sure, I'll admit, the Bard typically does have a slightly better chance at succeeding if both PCs are utilizing the same approach to achieve the same goal against an agnostic target over the course of a campaign, but does that mean the Fighter lacks any value in the social interaction pillar? It seems like some here are lamenting that. Our table just doesn't worry about it. Oh - I suppose it is also worth noting, for those unswayed by my desire to downplay the math: failure can be fun.