Definitely one of those who has been complaining about players not being proactive. It really feels like back “in the old days,” even as recently as 6-7 years ago, players would run things themselves, or give their characters reasons to get involved in other things that were going on, and now it feels like they sit back and wait for ways to get involved.
On The Eighth Sea, I even put together a huge list of about 20 plot hooks that players could follow up on, as well as a list of 4-5 “Quick Missions” that were suggestions for sidequest-like scenes that had stats pre-prepared and storylines sketched out. I had 3 people respond to plot hooks, most with vague “I would like to get involved in this” rather than any specific plans. One person besides myself used a Quick Mission.
With that complaining out of the way, I think that you’re asking some really good questions… I don’t know that I have any really good solutions (or even ideas).
Incentivizing people to RP outside of their circles.
Arx has a good method with randomscene, but that really only works when you provide XP for RP (although fractional Luck could be provided for this as well, I just don’t know that it’s enough of a carrot). If you have players who chased metaplot, I think that providing clues to different circles and OOCly letting everyone know who has clues might work. They would have to come up with their own IC reasons to contact people, but knowing who they should be working to might help.
I think that having proxy characters, or Handle characters, or allowing/encouraging spoofing of one alt with the other is a good way to encourage parallel scenes (and hence providing more opportunities to RP outside of “the one person you’re waiting for”). I don’t remember how we did it on The 100 (Grey2? Grey_Alt? Grey_Clone? Something like that), but that seemed to work well for allowing a character to be in multiple scenes at once.
This one is my real buggaboo. I hate it, it frustrates the hell out of me, and I don’t much know how to fix it. I think it’s a culture thing, where if you can create the right culture on your game and provide things for people to chase, they’ll go out and chase them, but I don’t know if MU* culture as a whole has been trained into passivity too much for that to work. On The Eighth Sea I tried specifically calling out players who had done this and providing them with Luck rewards, but… no one else seemed to step up. It felt like there were about 4-6 proactive players who dragged most everyone else along with them, and even they had to be reminded to follow up on breadcrumbs after plots.
Along the lines of the culture, it might be good for plotrunners to do an OOC wrap-up comment at the end of a plot, reminding people about the plotlines left dangling and letting them know how to follow after them. It totally, absolutely should not be necessary, but it might help…
I think going back to the previous two points, that the best way to encourage participation in the metaplot by the most people is to reward those who make their own fun (and fun for others) with spotlights within the metaplot. Have a player who did research on the big bad? Let them show their expertise and have it give a tangible benefit (even a +1 attack or defense is enough to make sure other players know that they helped out). Have a player who gathered other characters together? Make them the leader of a group.
On a way to appeal to more players, I think it’s important to make metaplot-critical missions that aren’t hack-and-slash. Maybe the PCs are working in a command center directing troops and the battle itself is only on-screen through reports to them? Or maybe the critical scene is a random-ass patrol running into an enemy leader and people of all “levels” getting a chance to try a diplomatic solution?
This is where I think it’s critical to have enemies that can be reasoned with and talked to… if the only way to interact with the enemies is to shoot them, then combat is all that matters.
I also think that it can be useful to have scenes “happening at the same time,” even if they’re separated by a day or two, and to have those scenes appeal to different people. If the objective is the punch a hole through enemy lines to take out the enemy leadership, you can have the first plot be coordinating forces to get the enemy where you want them (high-ranking leadership types), the second plot be actually breaking through enemy lines (general-purpose combatants, maybe new players, facing down against “standard” enemies), the third plot be taking on the enemy leader’s bodyguards (specialist combatants, dinos, facing down against “elite” enemies), and the fourth plot talking the enemy leader into a ceasefire (diplomatic folks). The critical part of this is to make sure that the players (and characters, but mostly the players) know that their part of the mission was only possible due to the actions of other PCs on the previous plots. If you can tweak the subsequent plots based on the results of the earlier plots, so much the better.
ETA: I would like to suggest two methods of discussion for this: mechanical solutions (new code, tools, wiki posts, etc) and cultural solutions (methods for Staff to communicate with players, mood-setters, etc). Of course, I mixed them in my post above, but… eh.