For the sake of argument, and to facilitate the concept behind this post, let's say there are three kinds of RPG campaigns.
[Yes, sure, of course there are more than three kinds, and the kinds I describe here don't cover everything except in the broadest sense, but indulge me so I can get this idea out, OK? Aces.]
The three types of games for our purposes here are:
In a Who game, it's all about the PCs. The campaign, and the vast majority of all the elements therein, are Player Character driven. Stories focus on the PCs, their goals, their drives, their background stories, and how the world/setting relates to them, and them to it, from the PCs' perspectives.
The benefits of this type of RPG are that the players will be very invested in their characters, and there is a likelihood of deeper characterization, and more role playing.
The main drawbacks of this type of campaign are that each player could be so focused on their own PC that they may not give much thought to the other players' PCs, the setting, or any adventure idea you've developed. If it isn't about them, it isn't important.
In a Where game, the setting is everything. OK, perhaps not everything, but it's the most important thing. Many IP based games fall into this category.
If you are playing in the Star Wars universe for example, and the adventure takes the PCs to Tatooine, then...wait...HOLY CRAP! We're on Tatooine! How awesome is that? The PCs will want to see Mos Eisley Spaceport, grab some blue milk at the Cantina, bullseye some Womp Rats, and drive a Pod Racer through Beggar's Canyon.
It's not just location however. It's the idea that the setting is king. A game set on Middle Earth, regardless of what story you, the GM, have developed, is really about running a campaign set on Middle Earth.
The benefits of this type of campaign are that the level of buy-in for fans of the setting is instantly deep, and familiarity with it's elements lets both the players, and the GM, focus on other things (You need only mention a thing. There is little to no need to describe it).
RIFTS seems to hold this kind of sway for many people here in NYC* (myself excluded).
Among the drawbacks of a Where game are that the players will spend more time exploring the setting, and doing all the cool things they can only do there, than they will thinking about your adventure. GM-created materials might be ignored, or even looked down upon. Also, those less familiar, or unfamiliar with the setting may be at a disadvantage, or at least feel like they are.
A What game is story driven. It is focused squarely on what is happening, what's going on. The plot, or plots, direct the PCs' courses of action, and define the setting. Who is on the adventure isn't that important, and neither are the rules, or tropes, of the genre (except as they relate to the tale being told). The story, and how the PCs interact with it, is what this kind of game is all about.
Benefits stemming from this type of game are that they are usually less chaotic, having clearly defined goals and directions for the PCs to go in, and they create a more satisfying narrative at the end of the campaign (whatever its length is).
Among the disadvantages of this approach are that the players can feel it's rail-roadie if not handled carefully, and PCs may seem interchangeable (or worse, disposable) since they don't matter overly much to the all-powerful plot.
Now, mull this over in your head a bit. Let it percolate a moment.
Let's reason out that it's highly unlikely any campaign is comprised of only one of these concepts. That wouldn't make sense. Sure, it's possible, I guess, but it doesn't make for a great game from where I'm sitting.
The real crux of the matter is this; How much of each category, Who, Where, and What, creates the type of game you want to run as a GM, or play as a player?
Not trying to get all deep, and philosophical up in here, but ask yourself, Is the game I am currently running/playing that game, or are the amounts of Who, Where, and What not in harmony with my preferences.
Logic dictates that the best possible campaign would have these three elements in equal amounts. Right?
Well, logic has little to do with fun, so let's toss that idea aside for a second. Yes, maybe that is the right mix for you, but is it the right mix for everyone? Surely not.
What about that young lady you keep running into down at your FLGS? The one who plays a lot of Monsterhearts, and wears those horn-rimmed glasses. You know who I'm talking about. You know as well as I do that a homogeneous, play-it-safe answer ain't gonna fly with her.
Be honest with me, and with yourself. One of the elements is going to take precedent over the others at your table, or would if it was up to you. Well it is.
Point of fact, I think that over the last few years my games have been like this:
When what I would prefer would be a situation closer to:
What about you? What's your preferred percentages, and have positively positioned the parts to perfection?
*RIFTS is, for some reason, very popular with gamers in the NY area. I myself do not care for the game. I don't know the origin of it's popularity, but I assume it has something to do with availability, and access to it. It can often be found in comic book stores as easily as game shops, or at least could for many years.