Lanefan
Victoria Rules
All of the pillars are vital to play but not always at the same moment, and sometimes any given character is simply going to be more or less important at any given timeThe problem here is that, by definition, all of the pillars are vital to play. That's literally why we call them pillars, as in, they are the foundation of the play experience. If they're supposed to be pillars, everyone is supposed to be able to meaningfully participate. Otherwise they're something else.
An analogy: if you're on the power play the odds are much lower (though not zero!) your goalie is going to be important at that moment than if you're on the penalty kill. A goalie is still vital to the team, however.
Same applies to D&D. If the mission of the moment requires stealth then your party sneak is going to be important while the plate-clad tanks aren't, and the reverse becomes true in a front-line melee. Having both on hand is still vital to the party.