one of the actual worst things that D&D instilled on rpg groups is the idea that you need a party of four. which i think came from the whole "fighter, rogue, wizard, cleric" template. and then 4E further refined that into the "Defender, Striker, Controller, Leader" archetypes, where you pretty much NEEDED each of those roles in your party.
but I still see this so much in other indie games as well where people will go for groups of 4+ and its just kinda maddening to me because anytime I have been able to have a group where its just me and three other players, that shit will sing. Pretty much any PbtA or FitD game is amazing at those numbers. Everyone's got a bond with the person to their left and right, its really easy to keep track of and going around the table is really snappy?
I remember there was this really cool looking mass discord blades in the dark event happening where all these games where going to be happening in tandem, and i know there was some thought to like interconnectivity or something. but i'd been somewhat interested in actually playing until the gm i was talking with explained how they were happy to have a group of 7+ and just... nah. you can split that up into two groups! Look, I love Friends at the Table as much as the next nerd but there's a good fucking reason they don't try and run a bunch of sessions where everyone is in the same place.
it is also nice because like... people are waiting for their turns less, there is less chance of people getting bored and zoning out. if you ARE doing something with initiative then you have the person before you and the person after you to worry about on your team. It's a lot less potential havoc.
kind of related: D&D4e's guideline is one of each role the game needs to work smoothly, and tells you what the roles are and why they're recommended, something a lot of games are very averse to explaining or don't seem to have considered?
There's the D&D3e/PF1e opaque class systems, where there is an intended way to play but party composition is more something you learn from other people who've played the game a lot rather than from the game (probably why 4e actually explained it to you, to help groups of all new players)
There's games like most PbtA games where party composition doesn't really matter because it's more character/story focused, but as Mitch said they still recommend 4 players for... reasons?
The one that annoys me most is classless systems who do the whole "you can be anything!" but don't actually work very well unless someone's character is covering a few specific bases, and don't really explain that. Using Shadowrun as an example, you don't need a wizard but you do need someone with astral perception, you not only need a hacker but they need a way to connect directly to things which can be covered by themselves or another character, and despite how much the fiction talks about them you don't need a street samurai the team just need to be collectively good at combat.
Just like... explain your game mechanics, blease, if the mechanics expect a certain team dynamic then "4-6 players" doesn't really cover it, and if they don't then you're putting people off of running for smaller groups for no real reason?
This is really interesting because I got into D&D in 4E, but I played with an experienced group who didnt like it and we switched back to 3rd and then to Pathfinder. And I honestly do really prefer the freedom you can get in those games to define your role more. Where a Fighter can be a Defender or a Striker. I had a Cleric with the highest mobility in the group and was essentially a controller with their ability to teleport themself and others around the map... But the point fwankie brings up is really good that you need to know what the hell is required.
You needed defense, healing, skills(traps & locks), skills(social), damage, magic and other positions to be able to operate fully. And generally people are able to fill one or two of those organically without any issue. But we had learned what we needed through experience. Which isn't necessarily bad but is not new player friendly. Because games like D&D are essentially full of lock and key dynamics. Gonna shout out Boss Keys by GMTK if you want good examination on those. But essentially the game is going to present you with obstacles you need specific keys to open. The keys in this case being skills/abilities. If no one in your party can disable device then you can get your whole adventure stymied when you get to a locked metal door. There's a magic trap? Welp, better send someone through and hope it doesn't kill them. But then there will be monsters that will damage you harshly enough you need someone who can heal or defend the party. Or ya know.. be able to convince someone to trust you all. And if you've got a good GM who is able to think on their feet then you might be able to figure out alternate ways around these, but sometimes it can be hard to figure out how you circumvent that door, ya know?
Some people will say don't throw things at your party that they can't handle or perform... which I think is bad advice. It's fun to throw them in the deep end, but you have to have ways for them to get out/around those checks you know they aren't good at. Like hey, that door might be a good way in past some shit, but you could take the front. Or where is that key? Maybe you can steal it/fight the guard who has it/or just bribe them to hand it over. My point being that if you don't cover all your bases, there should be ways around it. But that also means the players have to think harder and come at shit sideways which can be super rewarding play, but will burn some people out. I think about how there are some absolute freaks who love playing Larian games solo, just removing the entire party and doing it all with one PC. Or a particular one shot my buddies did in Pathfinder where most of the group couldn't make it, so it was just the GM, me, and one other PC. We had given us another level or two and we went into making our characters knowing the challenge of having to cover all a party's bases between two people and had a fucking blast. It was a really fun challenge and it wound up being balanced! But that was something we could do because we had been doing that for YEARS.
Anyway, this is really good advice and as I'm working on the next big update for Heroes by Hearthlight, I'm gonna try and figure out how to inform a party what they need need/what is expected for a Forged in the Dark game- but that's a chost for another time.