- Are Classes needed? (these are things that the game designer assumed were the most common activities in game, kinda like how D&D has fighter, wizard, rogue as its core since those are very common activities
Our group has lots of experience with classless systems, so not necessary for us in the least.
- Are Archetypes needed? (these are things that highlight the theme of the game, not the actual gameplay. Like vampire clans, where they have a theme to them 'Brujah anarch poet", but the player gets to truly customize their skills and powers, so could end up being "Brujah leader manipulator".
Yes, they are very helpful to illustrate the type/style of game this is and the activities the PCs are expected to be pursuing and how. And thus this provides another layer of world building. This doesn't need to be tied into the mechanics of creating a character, it could be just a list or a number of sample characters to give the flavour. So while character classes are a zero, this ranks high.
- Are Villains needed? (These are really obvious enemies that you pretty much are aware of from the get go. And they are always in opposition to your character, maybe can be bargained with, but usually just want to kill your character. Kinda like evil Liches, necromancer lords, demon dukes of hell, general hunters of your character types, etc etc etc)
Yes/no, in that specific villains don't necessarily need to be provided, but I prefer
some indication of the what this game's intended opposition is supposed to be. In many ways this is effectively the mirror of character Archetypes in being opposition Archetypes, be it specific individuals, monsters, organizations, environmental forces, thematic elements, and etc. And, again, this provides another layer of world building. So while villains ranks low, opposition archetypes rank as high as character archetypes.
- Are metaplots needed? (These are events or general situations in a game that force the group and GM to play into the game's own plots. Kinda like Lord of the Rings get rid of the ring, or wrath of the lich king invasions, or vampire's Camarilla and their masquerade rules, etc etc)
Not entirely. Following the bit above, some ideas of potential campaign directions (ie, Mission/Scenarios as you later note) is welcome and could nicely dovetail with the villainous archetypes. But an all-encompassing direction isn't required.
(That said, specific modules or books or etc that
do create a full metaplot are a nice add.)
How do you feel about a list of Missions/Scenarios for the players to choose from, and then the GM take each (or just one, either way is fine) and makes a campaign from it?
As noted above, I find these helpful as part of a greater archetype and campaign seed ideas portion of the book. Tell us what's so about the setting, what's neat about the setting, and then what the pressures/call to action are (or could be) in the setting, which then would include a starting seed, opposition, thematic elements, and possible scenarios and pathways to lead the campaign. Broaden this like that and I rank this high.
What if the game is like Grand Theft Auto? Like, just a big ol sandbox of mayhem and no real goals or plots. Maybe just a bunch of one sentence triggers for mini missions or whatever. (You can play into the GMs storyline plot, but that can always be set aside for sandbox , player-driven agendas.... is that too vague? Would players who never knew this game know what to do in the sandbox? )
There's a few games that I've read in the past where they present a raft of character stuff, gear stuff, combat option stuff, more gear stuff, still more gear stuff, a basic description of the world/universe and then... that's it. And that's not my cup of tea. Pure sandbox seems great in theory, but then what's the driver for me to pick this vs some other system/game? What is this optimized for? I very much want the Opposition Archetypes + Example Scenarios/Campaigns/Plots.