I think a Tier policy is not going to affect a game nearly as much as your staff culture and your XP gain rate will. Personally, I'm of a mind (at this point) that the best way to go is for everyone to start at around 100-200 (if its 1E), with a very slow XP gain rate. Higher XP rewards for STs, or significantly higher XP rewards for 'very deadly' scenes, made sense when I first started MUshing, but retrospectively they lead to the same problems. You get cliques of players/powergamers that are constantly running scenes for one another, and every one of those scenes includes someone taking agg damage and some monster hurling 30 die pools, and so the danger is 'real', but all the players are, again, powergamers. So then that clique skyrockets ahead of your average player on the XP roster. XP gain algorithms that cause low XP players to gain at a rate relative to the highest XP players are really goofy imo, because you end up with players gaining 50 or 90 XP a week. Players with 750 XP - especially if they are Sin-Eaters or Mages - are beyond unfuckwithable. They shouldn't even be player characters, they're incomprehensible. You might as well let folks play as True Fae, seriously. A 750 XP mage shouldn't be able to interact with other humans in any recognizable way.
Fear & Loathing's 'Guest Star' system was something different, and I caped for it for a while, because it did manage to create some cool RP and relieve pressure from the staff by effectively having players act as NPCs. Towards the end, I grew to dislike it, and in the weeks before it closed, I was turned off by the policy altogether, and urging for Paris/Stardust to do a relaunch without Guest Stars and focusing on a more level playing field with a more serious commitment to XP gain being staggered, and starting XP being raised periodically so new players weren't doomed to be trapped far behind dinos. Obviously, that didn't come to fruition, and the Guest Star policy is a big regret of mine, still.
San Francisco is interesting, because they are being a lot more mindful of XP gain than say, Fallcoast, and I won't be as derisive as Tempest but I have to say, the staffers on SF are much more attentive and invested in their player bases. Capping their spheres this early is an indicator of that. They don't want to be the biggest or most popular, they want to tell good stories, and be able to manage that, so they aren't overextending themselves or allowing a sandbox style environment do 'the work' for them. Those are the main reasons that I'm not totally put off by their tier policy; I mean, 400 XP mages at launch? Like, a third of the grid right now, in beta, is 400 XP mages. BUT, the gain rate is very closely minded, and the staffers are enthusiastic, and attentive. Do I think it would be better if their tiers were lower? Say, 100, 175, and 250? Yes. Do I think that their current setup, as it is, will damn them? Not really, it'll take more than just that.
