The Human Target said:
However the chances of a fighter having a decent Cha is fairly low. And as Hussar said they basically lack any other built in options for interaction boosts.
That doesn't really make 'em crap, though.
It might help to think of it this way: the way that you show that you are good or bad at the Interaction pillar of 4e is via Skill Challenges. If there's a dragon you need to talk with, or a king you need to persuade, Skill Challenges are how 4e wants you to handle that.
In that format, say our Level 1 Fighter has an 8 CHA and no training in Diplomacy and they're up against a Moderate DC 12.
But then, this is a 4e Skill Challenge, so why do they need to use Diplomacy? Or Intimidate? Or
any Cha-based skill? That player can use any skill she or he can convince the DM to let them use. Why can't they use, say, Endurance to show that they're not sweating the dragon's heat, or Athletics to impress the king by bench pressing his throne with him in it? One of the elements of the 4e Skill Challenge is that you don't have to make Diplomacy checks if you're not very good at it -- making a check with a skill you've got a high rank in is just a matter of selling the DM on it (and the DM is encouraged to say yes).
Since successes are what a Skill Challenge cares about, your successful Athletics check is pretty much the equal of the Bard's successful Diplomacy check. And even if, for some reason, you decided to roll your Diplomacy check and had only a 35% chance of success, that's still a 35% chance to have exactly the same effect that a bard would have doing the same thing. Once you make that check, it doesn't matter how high your modifier was, there's no way to affect the outcome of the scene aside from making successful checks.
So even if you make a non-talky Fighter, you're probably not going to suck at Interaction, because you can use whatever skill you'd like with a little thought. And even if you insist on making checks that you kind of suck at (2/5 win/loss ratio is not 0!), if you win, you're the equal of the talky characters. A successful Diplomacy check from Throg Smashly and Lllywendyr Charmington Diologus III has the same effect, even if Throg's got a lower chance of doing it.
Again, this is kind of more about the Skill Challenge design at this point. But if the SC is designed to eat up a big chunk of table time, it's actually
smart to let everyone be roughly the same in terms of achieving success -- you don't really want the Fighter's player twiddling their thumbs for a half hour while everyone else rolls dice around. Get in there, engage, come up with a way to contribute! So the equality is a good thing, if that's the point.
I'd argue that it's not the point, that the dialogue with the king is there so that the Interaction characters can shine, and it's OK if other characters don't shine there, because when it comes time to kill some bandits or discover secrets in a dungeon, that's their bailiwick. Which is why each challenge needs to be short and sweet, and why even in those, a minimum, boring way to contribute is needed for everyone.
I come back to the LotR comparison. Samwise might have not done much in many of the fights, but his ability to be the team cheerleader was critical for the success of the overall adventure. If I want to play my character like Samwise, I don't want to bugger around with mighty fightin' time too much, but I
really want to have a lot of options for dealing with keeping the party's courage and morale up over the long haul. And Gimli's going to be pretty useless there (though he'll be exactly who I want to kill goblins).
For D&D, it's not one-for-one, since we don't want Sam's player doing nothing while his character runs and hides, but it'd be nice to approach that dynamic, because it allows for interestingly differentiated characters. That kind of dynamic is only possible if Jackie's dwarf fighter CAN'T use Endurance to do the same thing my Halfling Gardener uses Craft (cooking) for. Under the Skill Challenge rubrick, you lose that distinction, and Fighters are the equal of Bards at Interaction challenges (even without high Cha), because Endurance and Diplomacy do the same thing in a Skill Challenge, and using either one is just a matter of giving the DM a reason to let you.