Kephess could be a big one, but he's more or less always in perma kick my *** mode, with no real spike phase, so I prefer the always on effects there, as while it'll help this time, next time I swap back in, i'll miss that 3.5% shields.
Kephess forces you to use tank swaps, which diminish the value of the passive relics in favor of the use relics. When you're not on Kephess, you don't have the benefit. When you are on Kephess, roughly every other time, you'll have that use proc up to bolster your survivability (meaning that the uptime goes up from 25% to roughly 50%, which definitely favors it over the passive). Whenever you're not tanking something, or are tanking something that ignores your defense, the passive relics are progressively less useful the longer you're on said target and the more useful the use relics become, assuming that you're going to switch back to a situation wherein the tank stats *are* useful.